As is known to us, theory is based on practice and     servers practice.

A. by chance  B. in turn   C. in return  C. by turn

Because prices of food and clothing and almost everything else in that country have steadily gone up, the buying          of the dollar has gone down.

A. energy   B. force  C. power  D. strength

I used to drink a lot of tea but these days I ＿＿＿coffee.

A.prefer B.preferred

C.have preferred D.am preferring

—— Has Jack finished his homework yet?

—— I have no idea； he ＿＿＿it this morning.

A.was doing B.had been doing

C.has done D.did

—When__________ and visit our exhibition next month?

— When_______, I will let you know.

A. will he come; he will come

B. will he come; he comes

C. does he come; he will come

D. does he come; he comes

A man does not know the difficulty of anything_________ he does it personally.

A. although     B. if            C. because       D. unless

__________ , we'll come to see you again.

A. If time will permit           B. Time permits

C. Time permitting               D. Time permited

Mr. White, who___________ moved to the south of France, still lives in London.

A. think to have                      B. think had

C. though have                        D. thought had

Mr. Zhang is mild in character. He never shouts__________ he is very angry.

A. to settle       B. setting      C. settled    D. being settled

--Shall Mary come and play computer games?

--No,__________ she has finished her homework.

A. when         B. if               C. unless    D. once