1. No city has cables _______laid____ directly.
a. lay
b. are laying
c. laid
2. Computers _____are used______ to perform series of mathematical operations.
a. are used
b. are using
c. have used
3. ____To reduce_______ power losses, thick wires should be used.
a. Reducing
b. To reduce
c. Having reduced
4. For information __transmitted_________, it must be attached to a radio – frequency carrier wave.
a. to be transmitted
b. will be transmitted
c. transmitted
5. Various installations _have been used__________ to transform electric power into mechanical and heat power.
a. have been used
b. are using
c. are being used
6. The experiment ___________ to be continued .
a. reports
b. is reporting
c. is reported
7. A computer ___________ to possess four main parts.
a. has been known
b. is known
c. knows
8. The atmosphere ___________ to extend several hundred kilometers above the Earth.
a. proves
b. has been proved
c. is proved
9. Transistor batteries ___________ to be used in systems that have to operate on weak signals, for example, in ultra-long-distance space communications.
a. expected
b. have been expected
c. were expected
10. Materials ___________ very high resistance are called insulators.
a. having
b. have
c. are having