1、Had Paul received six more votes in the last election, he ________ our chairman now.

　　A.must have been　　B.would have been　　C.were　　D.would be

　　2、Stressful environments lead to unhealthy behaviors such as poor eating habits, which ________ increase the risk of heart disease.

　　A.in turn　　B.in return　　C.by chance　　D.by turns

　　3、The tourist is prevented from entering a country if he does not have ________ passport.

　　A.an operative　　B.a valid　　C.an efficient　　D.an effective

　参考答案：

　　1、D　2、A　3、B