C. keep contact

D. carry on

8. He ______ in a youth hostel for two months when he was in London.

A. has stayed

B. stayed

C. had stayed

D. had been staying

9.And years later, she was proud that her son had read thousands of books, was awarded a PhD

in literature, and________ his own books, articles, poetry and fiction.

A. bid

B. recited

C. authored

D.spotted

10. — How ______ yobe so stupid as to believe him?

— Sorry, I did go out of my head somehow.

A. could

B. need

C.must

D. might

11. A number of major problems remain ______ about this new research project.

A. solving

B. to be solved

C. solved

D. to solve

12. I would like to particularly thank Professor Fisher, without whose instructions I ______ such a large English vocabulary.

A. didn’t acquire

B. wouldn’t acquire

C. hadn’t acquired

D. wouldn’t have acquired

13. Candidates shall remain in their seats ______ all the papers have been collected.

A. while

B. since

C. after

D. until

14. I promise to make yoall proud again in ______ direction life may take me.

A. however

B. wherever

C. whatever

D. whenever

15. It suddenly occurred to him _____he had left his key in the office.