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选词填空：1. The first experiment consists of stroking a rubber rod with some fur, and ___then____ in turn touching two small pith balls suspended from strings with the rod. The pith balls then swing apart, indicating that a repulsive force now acts between them. ___Next____, we stroke a glass rod with a silk cloth and touch two different suspended pith balls in turn with it. Once more the pith balls swing apart, indicating a repulsive force.2. Reflection from a brick wall is diffuse, ___while____ reflection from a mirror is specular.3. Electric force is, ___of course____, a vector quantity, with Eq. (21 – 1) giving only its magnitude.4. Thomson was able to establish by an ingenious experiment that electrons all have the same ratio of charge to mass. ___However____, he was not able to establish that all electrons are alike.5. The resistivities of nearly all substances vary with their temperatures. ____In general___, metals increase in resistivity with an increase in temperature ___while____ nonmetals decrease in resistivity.6. The frequency is the number of cycles executed per unit time. ___Hence____ frequency is the reciprocal of period T.7. But these first rubber overshoes and raincoats were all soft and sticky in summer, and unelastic in the winter when it was cold. ___In fact____, they might almost have been made of wax, only they were a bit stronger.8. With these formulas, we can convert temperatures from one scale to the other. ___For instance____, a Fahrenheit temperature of 70oF, which id normal room temperature, on the Celsius scale is 21oC.9. Unlike solids and liquids, gases do not have specific volumes at a particular temperature, __but_____ expand to fill their containers. The only way to change the volume of a gas is to change the capacity of its container. __However_____, even though its volume may remain the same, another property of a confined gas varies with its temperature, __namely___, the pressure it exerts on the container walls.10. Neither conduction nor convection can take place appreciably in the virtual void of interplanetary space. __Instead_____, the heat the earth receives from the sun arrives in the form of radiation.改写句子：X:1. The resistance of the human body is highly variable, principally because the conductivity of the skin is fairly low.2. When temperatures are greater than 80o C, this equation does not hold.3. Sweep methods of measuring frequency responses are commonly used in the laboratory today because their speed is great and their accuracy is adequate.4. When forward currents are relatively large the ohmic resistance of the contacts and the semiconductor material effectively increases the forward resistance.5. If pressure is constant, gases will expand when heated.6. While it is being compacted, considerable lateral pressure is exerted by the concrete.7. When all tests on the unit are completed, the results are recorded on an output device.8. If values of ω are small, the impedance of the capacitor is large relative to R.答案：1. …… because of fairly low conductivity of the skin.2. At temperatures greater than 80oC, …….3. ……because of their great speed and their adequate accuracy.4. For/With relatively large forward currents, ……5. At/For/With constant pressure, …….6. During compacting/compactification, (a) considerable lateral pressure is exerted by the concrete.7. At/On/After the completion of all tests on the unit, …….8. For/With small values of ω, ……XI：1. If the charging-time constant is reduced, both bandwidth and sampling efficiency will be improved.2. If the diode operates beyond this hyperbola, diode power dissipation will be in excess of its maximum rating of 1 W.3. If a current pulse is applied in the opposite direction, the magnetization will be reversed.4. If Eq. (1 – 2) is compared with Eq. (1 –3), it is shown that such a phase shift would result in system oscillation.5. If that current is removed, it will not be guaranteed that the galvanometer will return to its original position.6. If this number is substituted in Eq. (9 –4), the following expression is obtained.7. If the meter circuit is included in the feedback path, the effects of diode nonlinearities on circuit performance will be minimized.8. If this equation is differentiated, we can get the following expression.9. If the thickness of the lagging is increased, the heat losses will be reduced.10. If machines are tested by this method, there will be some loss of power.11. If these listings are studied, it will greatly help the programmer in finding any errors made in writing the program.12. If the temperature rose by 50oC, the device would be damaged.13. If such seven gates were to be cascaded, we would get an output of only 0.1 V.14. Because it is large in size, this resistor is often neglected.15. Since space is limited, only a brief discussion of quartz-crystal technology is allowed.16.. The fact that electrons is deflected by an electric field is used to control the direction of an electron stream in many electronic devices.答案：1. Reduction of the charging-time constant will improve both bandwidth and sampling efficiency.2. Operation beyond this hyperbola will result in diode power dissipation in excess of its maximum rating of 1W.3. Application of a current pulse in the opposite direction reverses the magnetization.4. Comparing Eq. (1 – 2) with Eq. (1 – 3) shows that such a phase shift would result in system oscillation.5. The removal of that current does not guarantee that the galvanometer will return to its initial position.6. Substituting this number in Eq. (9 – 4) yields [produces; gives; results in; leads to] the following expression.7. Inclusion of the meter circuit in the feedback path minimizes the effects of diode nonlinearities on circuit performance.8. Differentiation of this equation gives the following expression.9. Increasing the thickness of the lagging will reduce the heat losses.10. The testing of machines by this method will entail/result in some losses of power.11. A study of these listings will greatly help the programmer in finding any errors made in writing the program.12. A temperature rise of 50oC would damage the device.13. A cascade of such seven gates would yield an output of only 0.1 V.14. The large size of the resistor makes it possible to neglect it.15. Limited space allows only a brief discussion of quartz-crystal technology.16. The deflection of electrons by an electric field is used to control the direction of an electron stream in many electronic devices.翻译：1、这台机器的性能比那台好的多。