1.(2013·全國Ⅰ,24)If we ________ now to protect the environment, we'll live to regret it.
A.hadn't acted B.haven't acted
C.don't act D.won't act
答案:C 本題考查動(dòng)詞時(shí)態(tài)。句意:如果我們不行動(dòng)起來保護(hù)環(huán)境,我們會(huì)后悔的。根據(jù)主句的時(shí)態(tài)及從句中的now可知,條件從句要用一般現(xiàn)在時(shí)態(tài),故C項(xiàng)正確。
2.(2013·全國Ⅰ,27)When I first met Bryan I didn't like him, but I ________ my mind.
A.have changed B.change