9.去掉第二个and 10.√
7.be后加an 8.their→your
5.couldn’t→can’t 6.and→but
3.learn→learning 4.because→that
21-25CBCDD 26-30 BCBAB
短文改错答案:
1.去掉have 2.works→work
4.at finding 5.resulted in/ led to
6.located 7.proving 8.impolite 9.accepting 10.to solve