托福听力TPO1原文 Lecture 2
下面就让小编来为大家介绍一下托福听力TPO1原文中Lecture 2的文本内容吧，大家要好好把握，这些都是非常有价值的材料，希望能够给准备托福听力的同学带来帮助。
TPO 1 Lecture2GeologyListen to part of a lecture in a geology class.
ProfessorOk, let’s get started. Great. Today I want to talk about a way in which we are able to determine how old a piece of land, or some other geologic feature is - dating techniques. I’m going to talk about a particular dating technique. Why? Good dating is key to good analysis. In other words, if you want to know how a land formation was formed, the first thing you probably want to know is how old it is. It’s fundamental.
Uh… Take the Grand Canyon for instance. Now, we geologists thought we had a pretty good idea of how the Grand Canyon in the southwestern United States was formed. We knew that it was formed from sandstone that solidified somewhere between 150 and 300 million years ago. Before it solidified, it was just regular sand. Essentially it was part of a vast desert. And until just recently, most of us thought the sand had come from an ancient mountain range fairly close by that flattened out over time. That’s been the conventional wisdom among geologists for quite some time.
But now we’ve learned something different, and quite surprising, using a technique called Uranium-Lead Dating. I should say that Uranium-Lead Dating has been around for quite a while. But there have been some recent refinements. I will get into this in a minute.
Anyway, Uranium-Lead Dating has produced some surprises. Two geologists discovered that about half of the sand from the Grand Canyon was actually once part of the Appalachian Mountains. That’s really eye-opening news, since the Appalachian Mountain Range is, of course, thousands of kilometers to the east of the Grand Canyon. Sounds pretty unbelievable, right? Of course, the obvious question is how did that sand end up so far west? The theory is that huge rivers and wind carried the sand west where it mixed in with the sand that was already there.
Well, this was a pretty revolutionary finding. Um… and it was basically because of Uranium-Lead Dating. Why? Well, as everyone in this class should know, we usually look at the grain type within sandstone, meaning the actual particles in the sandstone, to determine where it came from. You can do other things too,
like look at the wind or water that brought the grains to their location and figure out which way it was flowing. But that’s only useful up to a point, and that’s not what these two geologists did.
Uranium-Lead Dating allowed them to go about it in an entirely different way. What they did was: they looked at the grains of Zircon in the sandstone. Zircon is a material that contains radioactive Uranium, which makes it very useful for dating purposes. Zircon starts off as molten magma, the hot lava from volcanoes. This magma then crystallizes. And when Zircon crystallizes, the Uranium inside it begins to change into Lead. So if you measure the amount of Lead in the Zircon grain, you can figure out when the grain was formed. After that, you can determine the age of Zircon from different mountain ranges.
Once you do that, you can compare the age of the Zircon in the sandstone in your sample to the age of the Zircon in the mountains. If the age of the Zircon matches the age of one of the mountain ranges, then it means the sandstone actually used to be part of that particular mountain range. Is everybody with me on that? Good. So, in this case, Uranium-Lead Dating was used to establish that half of the sandstone in the samples was formed at the same time the granite in the Appalachian Mountains was formed. So because of this, this new way of doing Uranium-Lead Dating, we’ve been able to determine that one of our major assumptions about the Grand Canyon was wrong.
Like I said before, Uranium-Lead Dating has been with us for a while. But, um… until recently, in order to do it, you really had to study many individual grains. And it took a long time before you got results. It just wasn’t very efficient. And it wasn’t very accurate. But technical advances have cut down on the number of grains you have to study, so you get your results faster. So I’ll predict that Uranium-Lead Dating is going to become an increasingly popular dating method.
There are a few pretty exciting possibilities for Uranium-Lead Dating. Here is one that comes to mind. You know the theory that earth’s continents were once joined together and only split apart relatively recently? Well, with Uranium-Lead Dating, we could prove that more conclusively. If they show evidence of once having been joined, that could really tell us a lot about the early history of the planet’s geology.
独白：听一段地质学课程。
教授：好吧，我们开始上课。今天我要谈一些关于如何测定地质年份和其他关于地质特征的方法——年代测量法。为什么我要讲一些特殊的测定法呢？一个准确的年代是一把打开分析之门的钥匙。换句话说，如果你想知道这块地质形成的原因，你要做的第
一件事就是搞清楚它的“年纪”了。这是基础的东西。嗯，举个大峡谷的例子。现代地质学家认为我们已经形成了一个没有太多瑕疵的关于美国西南部大峡谷起源的假说。我们推测它的形成源于 15 至30 亿年间砂岩的凝固。在成型之前，这些只是普通的沙子。本质上是沙漠的一部分。但最近，大多数人发现和认为这些沙子来源于古代山脉。这是那段时间地质学家的测量方法。但是现在我们得到了不同的方法和更多的惊喜，这种我们至今仍在使用的技术被称为“铀铅年份测试法”。
虽然说铀铅年份测试法问世已经有一段时间，但它也经历过几次改良。等一下我们就会讲到。总之，铀铅年份测试法给我们带来了一些惊喜。两个地质学家发现大峡谷大约一半的沙子实际上源于阿巴拉契亚山脉。这个发现真的令人瞠目结舌，因为大峡谷往东几千公里才到阿巴拉契亚山脉。听起来很不可思议，是吧?的确是这样，问题是那些沙子怎么能西移那么远？理论上是这样认为的：这些沙子被大河冲，狂风刮至大峡谷处汇集、混合并沉淀。
这确实是一个革命性的发现。嗯主要还是铀铅年份测试法的应用。为什么这样说？这样，正如在座的每一个同学应该知道的那样，我们通常关注沙砾内部的纹理类型，也就是沙砾里的微粒，来判定它来自哪里。我们也有别的方法，比如关注将沙砾带至该地的风或河流，然后推出它的流向。然而，这种方法只在一定程度上有用，那两个地质学家没有这样做。铀铅年份测试法给他们提供里全新的方式来推断沙砾的流向。他们做的是：他们研究沙砾里锆石的纹理。锆石是一种内含放射性铀的物质，而放射性铀对年代推算很有帮助。锆石源于熔岩，一种火山喷发的岩浆。这种岩浆随后会凝结。而当锆石凝结时，锆石里面的铀转化成铅。所以，如果你测量锆石里铅的含量，你可以推算纹理是何时形成的。之后，你就能从不同的山脉来断定锆石的年份。一旦你这样做，你就可以将样本沙石里锆石的年份和山脉里锆石的年份做比较。
如果样本沙石里锆石的年份与山脉里锆石的年份一致，那就意味着这里的沙石曾经作为这个山脉的一部分而存在。大家同意这个看法吗？很好。这样，铀铅年份测试法用于确认样沙里一半沙石和阿巴拉契亚山脉花岗岩的成形。所以，正因为这种，这种进行铀铅年份测试的新方法，我们有能力判定我们对大峡谷的重大假设之一是错误的。像我之前说过的那样，我们已经使用铀铅年份测试法有一段时间了。但，嗯，直到最近，要完成这样的测试，你还真得研究很多(沙砾的)纹理。当然，要得出结果是需要很长一段时间的。这样的做法其实效率并不高。同时，也谈不上精确。但是，技术的进步能缩减你需要研究的纹理的数量，这样你会更快地得到结果。我估计铀铅年份测试法将成为越发受人欢迎的年份测试法。在铀铅年份测试法里有几个令人兴奋的可能性。我想起的有这么一个：大家都知道地球大陆板块“始合近分”的理论吧?用铀铅年份测试法，我们能将这一理论论证得更具总结性。如果能有证据表明“始合”，那些证据就能给我们提供很多地球地质学的早期史料。
以上就是托福听力TPO1原文中Lecture 2的文本内容，希望大家能够用心体会，更多TPO文本内容小编稍后为您呈现。最后，小编祝大家在托福考试中取得好成绩！
托福TPO5综合写作阅读+听力原文+满分范文【雷哥托福】
托福TPO5综合写作阅读+听力原文+满分范文 【雷哥托福整理】 在备考托福写作的过程中，总是将托福的独立作文放在了第一位，但是实际上，综合作文也是占到了作文总分30分里面的50%的分值，不要等到分数出来了，才发现其实是综合作文的limited或者fair极大的影响了自己的分数。 考过的同学会发现托福综合作文分数不高，很大程度上是受我们听力实力的影响，我们很多托福考生的听力分数只有16分上下的时候，对于托福综合作文的听力妥妥的是束手无策，而且很多托福考生还感觉自己都听懂了，那也只能说明你听懂了大意，但是听力里面要的是每一个细节！请注意，是每一个细节！ 雷哥托福小托君给大家分享TPO1-33综合作文部分的阅读和听力文本全集与综合作文的满分作文，以及满分作文的解析。如果自己的托福综合作文分数如果可以很给力的话，就已经搞定了15分的分数，可极大地缓解托福独立作文的压力。文末教你如何使用这个材料。 TPO5 综合写作听力+阅读原文 Reading As early as the twelfth century A.D., the settlements of Chaco Canyon in New Mexico in the American Southwest were notable for their "great houses," massive stone buildings that contain hundreds of rooms and often stand three or four stories high. Archaeologists have been trying to determine how the buildings were used. While there is still no universally agreed upon explanation, there are three competing theories. One theory holds that the Chaco structures were purely residential, with each housing hundreds of people. Supporters of this theory have interpreted Chaco great houses as earlier versions of the architecture seen in more recent Southwest societies. In particular, the Chaco houses appear strikingly similar to the large, well-known "apartment buildings" at Taos, New Mexico, in which many people have been living for centuries.
托福TPO12综合写作阅读原文+听力原文+满分范文
为了帮助大家高效备考托福，为大家带来托福TPO12综合写作阅读原文+听力原文+满分范文，希望对大家备考有所帮助。 托福TPO12综合写作阅读原文文本： Jane Austen (1775-1817) is one of the most famous of all English novelists, and today her novels are more popular than ever, with several recently adapted as Hollywood movies. But we do not have many records of what she looked like. For a long time, the only accepted image of Austen was an amateur sketch of an adult Austen made by her sister Cassandra. However recently a professionally painted, full-length portrait of a teenage girl owned by a member of the Austen family has come up for sale. Although the professional painting is not titled Jane Austen, there are good reasons to believe she is the subject. First, in 1882, several decades after Austen's death, Austen's family gave permission to use the portrait as an illustration in an edition of her letters. Austen's family clearly recognized it as a portrait of the author. So, for over a century now, the Austen family itself has endorsed the claim that the girl in the portrait is Jane Austen. Second, the face in the portrait clearly resembles the one in Cassandra's sketch, which we know depicts Austen. Though somewhat amateurish, the sketch communicates definite details about Austen's face. Even though the Cassandra sketch is of an adult Jane Austen, the features are still similar to those of the teenage girl in the painting. The eyebrows, nose, mouth, and overall shape of the face are very much like those in the full-length portrait. Third, although the painting is unsigned and undated, there is evidence that it was painted when Austen was a teenager. The style links it to Ozias Humphrey, a society portrait painter who was the kind of professional the wealthy Austen family would hire. Humphrey was active in the late 1780s and early 1790s, exactly the period when Jane Austen was the age of the girl in the painting. 托福TPO12综合写作听力原文文本： Professor：The evidence linking this portrait to Jane Austen is not at all convincing. Sure, the painting has long been somewhat loosely connected to Austen's extended family and their descendants, but this hardly proves it's a portrait of Jane Austen as a teenager. The reading's arguments that the portrait is of Austen are questionable at best.First, when the portrait was authorized for use in the 1882 publication of her letters, Jane Austen had been dead for almost 70 years. So the family members who asserted that the painting was Jane had never actually seen her themselves. They couldn't have known for certain if the portrait was of Austen or not.Second, the portrait could very well be that of a relative of Austen's, a fact that would explain the resemblance between its subject and that of Cassandra's sketch. The extended Austen family was very large and many of Jane Austen's female cousins were teenagers in the relevant period or had children who were teenagers. And some of these teenage girls could have resembled Jane Austen. In fact, many experts believe that the truesubject of the portrait was one of those relatives, Marianne Kempian,
老托福93篇听力原文
1 Community service is an important component of education here at our university. We encourage all students to volunteer for at least one community activity before they graduate. A new community program called "One On One" helps elementary students who've fallen behind. Y ou education majors might be especially interested in it because it offers the opportunity to do some teaching—that is, tutoring in math and English. Y ou'd have to volunteer two hours a week for one semester. Y ou can choose to help a child with math, English, or both. Half-hour lessons are fine, so you could do a half hour of each subject two days a week. Professor Dodge will act as a mentor to the tutors---he'll be available to help you with lesson plans or to offer suggestions for activities. He has office hours every Tuesday and Thursday afternoon. Y ou can sign up for the program with him and begin the tutoring next week. I'm sure you'll enjoy this community service and you'll gain valuable experience at the same time. It looks good on your resume, too, showing that you've had experience with children and that you care about your community. If you'd like to sign up, or if you have any questions, stop by Professor Dodge's office this week. 2 I hope you've all finished reading the assigned chapter on insurance so
托福听力TPO1原文 Lecture 4
下面就让小编来为大家介绍一下托福听力TPO1原文中Lecture 4的文本内容吧，大 家要好好把握，这些都是非常有价值的材料，希望能够给准备托福听力的同学带来帮助。 TPO 1 Lecture 4BiologyNarratorListen to part of a lecture in a biology class. ProfessorFor today’s discussion, we’ll review the case study on how some animals have behaviorally adapted to their environments. Now you had to read about two animal species, the Eastern marmot and the Olympic marmot. Marmots are rodents. They are large ground squirrels, about the size of an average house cat. And they live in a variety of habitats. And even though they spend the significant portion of the year hibernating, according to this case study, marmots are still considered excellent subjects for animal behavioral studies. Why is that? StudentWell, when they are not hibernating, you can find them in open areas. And they are pretty active during the day, which makes them easy to observe, right? ProfessorUh-huh, so first let’s discuss the Eastern marmots. They reside throughout the eastern region of North America where there is a temperate climate, where the growing season lasts for at least five months of the year, which is when they do all their mating, playing and eating. StudentOh, I see. At first I wasn’t sure what growing season meant, just from the reading. But now I get it. It's the amount of time it takes for them to grow, right? So it would be five months? ProfessorUmm? Oh, uh… I’m sorry but no. It has nothing to do with that. It's not about the time it takes for Eastern marmots to grow. It’s when the food is available. That is when it’s not covered in snow and there is no frost covering the grass and, umm, vegetative parts of a plant’s herbs and the flowers the marmots like to eat. So growing season refers to the availability of the food they eat, OK? So now how would you describe the Eastern marmots’ social habits? StudentWell, they are really territorial, and loners, and just so aggressive even with other Eastern marmots. And their mating ritual is just so impersonal. ProfessorUh-huh? Now when they emerge in the spring from hibernation, the mating process begins. For them, well, they come together to mate and then they
托福听力原文
0401 W: Hey Steve, got any plans for tonight? M: Hi, Jane. No, I don't think so. Why? Got any suggestions? W: In fact, I do. I just got two tickets to the opening of the exhibit of the reprints by Julia Margaret Cameron. I would have tomention it earlier, but I was on the waiting list for these tickets and I wasn't sure I'd even get them. M: An exhibit, huh? I like such things. But I don't know who Julia…… W: Margaret Cameron! She was a photographer in the 1800s. She is interesting to art-historians in general and students ofphotography in particular because she ... how should I say, change the aesthetics for photography. M: What do you mean? W: Well, her specialty was portraits and instead of just making a factual record of details like most photographers did, you know, justcapturing what a person look like in a dispassionate thought of way. She, like a portrait painter, was interested in capturing hersubject's personality. M: Interesting! How did she do that? W: She invented a number of techniques that affect the picture. Like one of these things she did was blur images slightly by using asoft focus on the subject. That's pretty common now. M: Yeah, seen that. Who did she photograph? W: Famous people of her day, Alfred Lord Tennyson, Henry Wadsworth Longfellow, Charles Darwin, I don't know who else. We'll seeat the exhibition. M: You really pick my curiosity. I am going to enjoy this. 31. What is the conversation mainly about? (A) A famous photographer 32. What did Julia Margaret Cameron emphasize in her portraits? (C) Her subject's personality 33. According to the conversation, what unique photographic technique did Margaret Cameron use? (D) Soft focus 34. What will be the subject of the pictures at the exhibit? (C) Well-known people M: Do you want to the movies with on Saturday? W: Thanks, but I have to study my research project. I'm taking that same anthropology course you took with Prof. Grady. M: The one on ethnographic interviewing? Oh, good! I'm sure you'll get a lot out of it. W: I have to admit the word "ethnography"(人种学) scared me a little at first. It seems so technical. But then when she explained that it's what anthropologists do, you know, how they investigate and record aspects of a culture, I didn't seem so intimidating! M: Yeah, it's all part of the fields work anthropologists conduct and it's good to start doing that now before you become a graduatestudent and have to conduct large projects yourself. Who are you going to interview? W: You know the publishing office where I used to work? Vivian, the woman I worked for, she's been a manager there for over 30years and had seen a lot of changes in the industry. I thought I'd start out by interviewing her about how the people in the officeinteract with each other and with outside clients. M: Isn't it funny how we use the thing that anthropologists study to foreign cultures and had the travel halfway across the world to doit? The best part of that course is that it shows you that ethnographic research can also be done on a familiar ground. W: Yeah. I got the idea from my project from reading Robert Marshal's study of office life and I
老托福听力30篇下载之地球内部构成(原文+翻译)
官方网站：https://www.360docs.net/doc/2916547753.html, 老托福听力30篇下载之地球内部构成（原文+翻译） 老托福听力30篇下载之地球内部构成（原文+翻译）。托福考试备考资料你选老托福听力30篇了吗？没选也不要紧，下面小马编辑为大家精选了老托福听力30篇中地球内部构成相关的原文及翻译，同学们不用下载完整版的老托福听力30篇也可以，还等什么，赶快来下载吧。 老托福听力30篇是托福听力考试备考必备的材料，下面为大家整理了老托福听力30篇中地球内部构成相关内容，还附带有原文及翻译，同学们可下载进行练习。 I'm glad you brought up the question of our investigations into the makeup of the Earth's interior. In fact, since this is the topic of your reading assignment for next time, let me spend these last few minutes of class talking about it. There were several important discoveries in the early part of this century that helped geologists develop a more accurate picture of the Earth's interior. The first key discovery had to do with seismic waves. Remember they are the vibrations caused by earthquakes. Well, scientists found that they traveled thousands of miles through the Earth's interior. This finding enabled geologists to study the inner parts of the Earth. You see, these studies revealed that these vibrations were of two types: compression or P waves and shear or S waves. And researchers found that P waves travel through both liquids and solids, while S waves travel only through solid matter. In 1906, a British geologist discovered that P waves slowed down at a certain depth but kept traveling deeper. On the other hand, S waves either disappeared or were reflected back, so he concluded that the depth marked the boundary between a solid mantle and a liquid core. Three years later, another boundary was discovered, that between the mantle and the Earth's crust. There's still a lot to be learned about the Earth. For instance, geologists know that the core is hot. Evidence of this is the molten lava that flows out of volcanoes. But we're still not sure what the source of the heat is. 我很高兴你对我们关于地球内部构成的研究提出问题。事实上，这个话题将是你们的下一个阅读作业，现在让我用占用课堂上的几分钟说说这个话题。在这个世纪有几个重要的发现，它们帮助地质学家显影出一张更精准的地球内部构成图。第一个关键的发现与震波有关。记住震波是地震引起的震动。于是科学家发现这些震波是穿过数千英里从地球内部传来的。这个发现使科学家能够研究地球里面的部分。你看，这些研究显示震动有两种类型：压缩波或者叫P型波，和切变波或者叫S型波。研究人员还发现P型波可以穿过液体和固体，而S型波只能穿过固体物品。在1906年，一位英国地质学家发现P型波在一定的深度传播很慢，但是会继续向更深的地方传播。另一方面，S型波不是消失就是被反射回来，所以他推断出深度标志着固体地幔与液体地心的边界。三年后，另一个边界被发现，是地幔与地壳的边界。还有很多关于地球的奥秘等着我们去了解。例如，地质学家根据从火山流出的熔岩知道地心是炎热的，但是我们还是不能确定地心热量的来源是什么。
托福听力原文
Conversation 1: Passage 1 Man: Hi. Are you Paula? $ Woman: Jim? $ Man: Hi. Nice to meet you. $ Woman: Glad to meet you. $ Man: So, you need some tutoring in English? $ Woman: Yeah. I'm taking English composition, and I'm not doing very well on my essays. $ Man: Right. Um, well, first let's see if we can figure out a time to meet . . . that we're both free. $ Woman: Okay. $ Man: How about Mondays? Maybe in the morning? I don't have any classes until eleven on Mondays. $ Woman: That would work, but I was hoping we could, you know, meet more than once a week. $ Man: Oh. Well, Tuesdays are out. I've got classes and, uh, I work at the library part time on Tuesdays and Thursdays. Bu t I could get together on Wednesdays. $ Woman: In the morning? $ Man: Probably nine-thirty would be best. That way we'd have an hour to work before I'd have to get ready for my eleven o'clock.
托福听力TPO14原文Lecture4
托福听力TPO14原文Lecture4 下面就让小编来为大家介绍一下托福听力TPO14原文中Lecture4的文本内容吧，大家要好好把握，这些都是非常有价值的材料，同时，大家也可以登录前程百利论坛进行TPO练习辅导，希望能够给准备托福听力的同学带来帮助。 TPO14Lecture4Archeology Professor：When we think of large monumental structures built by early societies and Egyptian pyramid probably comes to mind.But there are some even earlier structures in the British Isles also worth discussing,and besides the well-known circle of massive stones of Stonehenge which don’t get me wrong is remarkable enough,well,other impressive Neolithic structures are found there too.Oh,yes,we are talking about the Neolithic period here,also called new Stone Age,which was the time before stone tools began to be replaced by tools made by bronze and other metals.It was about5000years ago,even before the first Egyptian pyramid that some of amazing Neolithic monuments---tombs, were racketed at the very size around ironed Great Britain and costal islands nearby.I am referring particular to structures that in some cases,look like ordinary natural hills.But we definitely build by humans,well-organized communities of human’s to enclose a chamber or room within stone walls and sometimes with a high,cleverly designed sealing of overlapping stones.These structures are called Passage Graves,because in the chamber,
托福听力TPO1原文 Lecture 1
家要好好把握，这些都是非常有价值的材料，希望能够给准备托福听力的同学带来帮助。 TPO 1 Lecture 1Contemporary artListen to part of a lecture in a contemporary art class. ProfessorOk, I’m going to begin this lecture by giving you your next assignment. Remember I said that at some point during this semester I wanted you to attend an exhibit at the Fairy Street Gallery and then write about it? Well, the exhibit that I want you to attend is coming up. It’s already started in fact, but it’ll be at the gallery for the next month, which should give you plenty of time to complete this assignment. The name of the artist exhibiting there is Rose Frantzen. Frantzen’s work may be unfamiliar to you since she’s a relatively young artist. But she’s got a very unusual style, compared to some of the artists we’ve looked at this term. But anyway, Frantzen’s style is what she herself calls Realistic Impressionism. So you’ve probably studied both of these movements separately, separate movements, Realism and Impressionism, in some of your art history courses. So who can just sum these up? StudentWell, Impressionism started in the late 19th century. Um…the basic impressionist style was very different from earlier styles. It didn’t depict scenes or models exactly as they looked. Um… Impressionist painters tended to apply paint really thickly, and in big brushstrokes, so the texture of the canvas was rough. ProfessorGood. What else? What were the subjects? StudentWell, a lot of impressionist artists painted everyday scenes, like people on the streets and in cafes, uh, lots of nature scenes, especially landscapes. ProfessorGood. So when you go to the exhibit, I really want you to take a close look at a certain painting. It’s a farm scene. And you will see it right as you enter the gallery. The reason I think this painting is so important is that it stresses the impressionist aspect of Frantzen’s style. It’s an outdoor scene, an everyday scene. It’s kind of bleak, but you can really see those broad brushstrokes and the blurry lines. The colors aren’t quite realistic. The sky is kind of, well an unnatural pinkish yellow. And the fence in the foreground
老托福听力1~2原文及翻译
1 Community service【社区服务】is an important component of education here at our university. 在我们大学这里，社区服务是教育的一个重要组成部分。 We encourage all students to volunteer for at least one community activity before they graduate. 我们鼓励所有的学生在他们毕业前至少志愿参加一次社区活动。 A new community program called "One On One"【一对一】helps elementary students who've fallen behind. 一个新的社区计划，叫做“一对一”，帮助落后的小学生 You education majors might be especially interested in it because it offers the opportunity to do some teaching—that is, tutoring in math and English. 你们教育专业的可能对此很感兴趣，因为它提供了教学的机会，也就是说，辅导数学和英语 You'd have to volunteer two hours a week for one semester. You can choose to help a child with math, English, or both. 你们必须在一学期内每周志愿服务两个小时。你可以选择帮助一个孩子的数学、英语或两个都帮。 Half-hour lessons are fine, so you could do a half hour of each subject two days a week. 半个小时的课程就好，所以你可以每项做半个小时, 一周做两天。