Dr. Robert went to New York, bought some books and ___.

A. was walking B. walked

C. walking D. had walked

A. Don’t

B. Mustn’t

C. Needn’t

D. Can’t

A. Will have studied

B. Study

C. Will study

D. Have studied

A. Only by working hard we can

B. By only working hard we can

C. Only by working hard can we

D. Only we can by working hard

A. Anything

B. One thing

C. Nothing

D. none

A. If

B. Although

C. As

D. however

A. How much cost it will be

B. How much has it cost

C. How much it will cost

D. How much will it cost

A. On duty

B. On business

C. On board

D. On the spot

A. Highly

B. Well

C. Greatly

D. enough

A. After all

B. All over

C. Above all

D. First of all