Chapter 9 The Passive Voice The range of

Chapter 9 The Passive Voice • The range of transmission frequencies that can be carried on a communications line is referred to as the bandwidth of the line. Bandwidth is a very important ingredient in data communications because the capacity (stated in bits per second) of a communications path is dependent on the bandwidth of the path. If the telephone channel were increased from a bandwidth of 3 kilohertz (k. Hz) to 20 k. Hz, it could carry all the characteristics of the voice. This also holds true for transmitting data; a better data transmission rate can be achieved with a greater bandwidth.

• 9. 1 The Passive Voice Converted Into the Active Voice • 9. 1. 1 The Original Subject Unchanged • While a current is flowing through a wire, the latter is being heated. • The ripple is very much reduced by the double filtering action. • The definitions of the trigonometric functions were given in Section 3 -2.

• Sometimes the communications would be seriously disturbed by solar spots. • These problems must be solved before a chain reaction starts. • The liquid fuel rocket is continuously improved. • If the amount of positive and negative charges is varied, the electron stream can be made to bend up or down in varying amounts.

• 9. 1. 2 Changing Original Subject Into Object • A knowledge of statistics is required by every type of scientist for the analysis of data. • Earthquakes seem less easy to be controlled by man than weather. • Mechanical energy can be changed back into electrical energy through a generator.

• 9. 1. 3 Adding a Proper Subject to Make the Chinese Version Smooth • At that time it was found that an electric current can produce the heating effect. • Silver is known to be the best conductor. • When one of the charged bodies has a polarity opposite to the other, there is said to be a difference of potential between them.

• 9. 2 The Passive Structure Converted Into a Sentence Without a Subject • If a source of e. m. f is applied to a closed circuit, the current will be found to flow continuously in the circuit. • Attempts were made to develop a new technique for breeding rice variety. • In this case, a 2 -m. V signal may be applied to the input of the amplifier. • A film of oil is inserted between the sliding surfaces of a bearing.

• If a 10 -kilogram box is lifted one meter, the work done is 10 -kilogram-meter. • With all its advantages the accuracy of the new dating method using radioactive C-14 can’t be blindly trusted.

• 9. 3 The Passive Structure Remaining Unchanged • Besides voltage, resistance and capacitance, an alternating current is also influenced by inductance. • Radars have been used extensively for mapping geological structures and features. • Each dot of light is translated by the camera tube into an electronic signal. • Sound is carried by air, and without air there can be no sound.

• 9. 4 Rendering Into Chinese by Using “是…的” • We assume that this condition is fulfilled in all that follows. • Resistance is measured in ohms. • In actual practice separate subtractors are not used. • Some plastics have been discovered by accident. • Air, as well as water, is needed to make plants grow. • Electromagnetic waves carry the energy which is received from the current flowing in the conductor.