21. Mrs Smith had ____8-year-old son who has ____ gift for painting. He has won two national prizes.
A. a, a B. an, the C. an, a D. the, a
22.-----Look, Tom has fallen asleep.
-----Oh, he _____ too late yesterday evening.
A. might stay up B. should have stayed up
C. could stay up D. must have stayed up
23. Only after my parents came____ .
A. did the computer repair B. they repaired the computer
C. was the computer repaired D. the computer was repaired