21. Schools have been lengthening the school day to raise test marks, which be costly if schools need air conditioning on hot days.
A. might B. can C.dare D. need
22. The function of an advertisement is that it can customers to buy the kinds of goods.
A. employ B. persuade C. prepare D. urge
23. You'd better ask for help at the beginning rather than wait until a busy period everyone is rushed off their feet.
A, that B. which C. when D. where
24. Deliberately push yourself out of your . Try things that you do not normally try.
A. origin B. budget C. routine D- identity
25. Leaders of the two countries have had contacts and
continuously promoted their political mutual trust.
A.frequent B. secure C. specific D.social
