281.I was having a nap when suddenly the telephone rang.

A. 　he cross

B. 　him cross

C. 　him crossed

D. 　he crossing

A. 　was playing

B. 　am playing

C. 　play

D. 　played

A. 　Never mind

B. 　It doesn’t matter

C. 　Not at all

D. 　No thanks

A. 　cooked

B. 　was cooking

C. 　cooks

D. 　has cooked

A. 　Yes, twenty years ago

B. 　Since twenty years

C. 　Twenty years before

D. 　For twenty years

A. 　will

B. 　is to

C. 　is going to

D. 　should

A. 　supplement

B. 　replace

C. 　add

D. 　eat

A. 　In a university.

B. 　Very hard.

C. 　Mathematics.

D. 　At nine in the morning.