12. Commercial expansion from city to suburb has affected the way people in the United States _____ .
A. living and working B. they live and work
C. live and work D. to live and to work
13. _____ , it is not difficult to drill a hole on it.
A. Hard as the diamond is B. Hard as is the diamond
C. Although hard the diamond is D. Hard though is the diamond
14. ____ without a word annoyed his parents.
A. His leaving home B. Him leaving home
C. Him having left home D. Him being left
15. I don’t suppose anyone will come, _____ ?
A. do I B. don’t I C. will they D. won’t they
16. The great speed of light explains ____ we see things happen at the exact moment ____ they are happening.
A. that…in which B. why…when C. what…when D. how…in which
17. I didn’t hear the phone. I ____ asleep.
A. must be B. must have been C. should be D. should
18. The big tower ____ in the Tang dynasty broke down last week.
A. built B. being built C. having been built D. to build
19. This text is ____ than that one.
A. much difficult B. much less difficult
C. difficulter D. many more difficult
20.I was so angry at all ____ he was doing ____ I walked out.
A. which, that B. what; that C. that; which D. that; that