11. The reason _____ I can‘t come is that I have to prepare for the coming exam.
A. for
B. as
C. because
D. why
12. She studied hard at school when she was young; _____ contributes to her success in her career.
A. that
B. so that
C. so
D. which
13. Sound waves travel in the air in much the same way _____ water waves spread on the water.
A. as
B. that
C. where
D. in which
14. I‘ve got a bottle of beer, but I haven’t got anything _____ I can open it with.
A. that
B. what
C. where
D. which
15. Writers can accurately describe objects ______ have never seen.
A. who
B. if they
C. they
D. that
16. It wasn‘t such a good present _____ he had promised me.
A. that
B. as
C. which
D. what
17. Perhaps the day will come _____ people will be able to breathe clean air in cities.
A. when
B. while
C. as
D. since
18. To make up an objective test, the teacher writes a series of questions, _____ has only one correct answer.
A. each of which
B. some of which
C. which
D. what
19. A higher crime rate exists in cities _____ a large percentage of unemployment.
A. where have
B. that have
C. which they have
D. that having
20. Scientists call Newton‘s idea _____ gravitation reaches throughout the universe the law of universal gravitation.
A. when
B. which
C. that
D. where