I( )to interrupt a man when he’s busy working.

A. improves

B. improves on

C. betters

D. proves

A. Now that B. So far C. Though D. Even if

A. what B. whatever C. where D. however

A. by contrast B. by nature

C. on the whole D. on the average

A. instead of B. in addition to

C. as well as D. at the cost of

A. signs B. signals C. symbols D. marks

A. are used to go B. use to go

C. used to go D. were used to go

A. for B. at C. to D. on

A. couldn’t I B. don’t I

C. could you D. will you

A. with B. for C. on D. under