从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. — Do you think advertisement is _______ help when you look for a job.
— Well, it depends. Anyway, it gives me more of_______ chance to try.
A. a; a B. a; the C. the; the D. /; /
22. You ought to have thought of that, but you _______.
A. haven’t B. didn’t C. don’t D. can’t
23. The place _______ the bridge is supposed to be built should be _______ the cross river traffic is the heaviest.
A. which; where B. at which; which C. at which; where D. which; in which
