11. It was my grandfather _____ helped mike mend his bike this morning.

A. that B. whom

C. which D. what

12. It was this morning _____ my grand father helped mike mend his bike this morning.

A. that B. whom

C. when D. which

13. It was because it rained heavily last night _____ he didn‘t come to the evening school.

A. that B. so that

C. so D. when

14. Air， or _____ is called atmosphere， surrounds the whole earth.

A. it B. that

C. which D. what

15. In short， _____ he lives， a man belongs to some society.

A. whatever B. whenever

C. wherever D. whichever

16. Nowhere else in the world _____ more attractive scenery than in Switzerland.

A. you can find B. is found

C. can you find D. has been found

17. I couldn‘t find peter， _____ did I know where he had gone.

A. never B. either

C. nor D. as

18. Not until I reminded him for the third time _____ working and looked up.

A. that he stopped B. does he stopped

C. did he stop D. that he stopped

19. Not until most of the people had left the airport _____ his sister was there.

A. that he saw B. had he seen

C. did he see D. that he had seen

20. _____ the importance of wearing seat belts while driving.

A. Little they realize B. They little do realize

C. Little realize do they D. Little do they realize