从题中所给的A、B、C、D四个选项中选出可以填入空白处的最佳选项。
21. Mom, I lost ____ diamond ring my boyfriend bought for me. Could you keep _____ eye out or it when you clean the house?
A. the; an B. a; an C. a; the D. the; the
22. On the contrary, I think it is Daniel, _____ you, ______ to blame.
A. more than, are B. rather than, that is
C. less than, who are D. rather than, is
23. It’s a program designed to______ mainly to 10 to 16 year-olds.
A. appeal B. attach C. contribute D. refer
