21.I’m_____building a new zoo because I think zoos are terrible places for animals to lives in.
A.against B.on C.in D.for
21.A【解析】根据题干“I think zoos are terrible places for animals to lives in.”可知说话人反对建新的动物园。against是介词，be against doing sth.反对做某事。
22. Many a boy _________ playing basketball.
A. likes B. like C. to like D. have hke
23.Nobody but the twins __________some interest in the project till now.
A. shows B. show C. have shown D. has shown
24.I don't think __________ possible to finish so much work within so short a time.
A. this B. that C. its D. it
25. --I'm surprised to hear that Sue and Paul have__________.
--So am I. They seemed very happy together when I last saw them.
A. broken up B. finished up
C. divided up D. closed up
25.A【解析】考查动词短语辨析。break up“断绝关系”；finish up“结果成为，最终到来”；divide up“分成。分享”；close up“(伤口)愈合”。根据旬意，可知此处指二人关系破裂，故选A。