21. The number of the people invited ___ fifty, but a number of them__ absent for different reasons.
A. are, is B. is, are C. is, is D. are, are
22. It was in the street_________ I met Mary yesterday.
A. that B. when C. where D. what
23. — Could I use your computer for a few minutes, please?
— __________. I’m not using it myself.
A. Come on B. It depends C. Go ahead D. That’s great
