21.What__________ great fun it is to play_____________ basketball after school.
A. a; / B. a; the C. /; / D. /; the
22. Hurry up！The train __________. You know it __________ at 8:30 am.
A. leaves; leaves B. is leaving; leaves
C. leaves; is leaving D. is leaving; is leaving
23. -----David has made great progress recently.
-----__________, and __________.
A. So he has; so have you B. So he has; so you have
C. So has he; so have you D. So has he; so you have
