1. Electronic devices ___ for scientific research since the 1940s.
A. were used C. had used
B. have been used D. was being used
2. I'm sorry I didn't call earlier, but I ___ your message a minute ago.
A. received C. had received
B. have received D. receive
3. The first fully electronic computers ___ for breaking secret military codes during World War II.
A. has been developed C. had developed
B. developed D. were being developed
4. The factory producing pirate CDs ___.
A. were closed C. was being closed
B. has been closed D. are closing
5. Satellites ___ to transmit telephone calls across countries and oceans.
A. has been used C. were being used
B. are used D. used
6. ___ they already tested the new security system?
A. Do C. Was
B. Are D. Have
7. ___ they arrested for illegally copying video recordings.
A. Were C. Had
B. Did D. Will
8. What ___ RAM mean?
A. was C. is
B. has D. does
9. One of the best things about mobile phones is that you can send ___ messages to your friends having the phone.
A. to write C. written
B. wrote D. writing
10. You were lucky enough ___ the bug in time.
A. to detect C. detecting
B. detected D. detects
11. Computers are now ___ than they used to be, but the computer programs you need to operate them can be quite expensive.
A. cheap C. cheaper
B. more cheaper D. the most cheap
12. You ___ copy this text; I will give you a Xerox of this page.
A. mustn't to C. may not
B. should D. can't to