问题
选择题
(2013·皖南八校联考)________ here yesterday，he could have seen Jackie Chan.
A．If Bob has come
B．If Bob came
C．If Bob had come
D．If Bob should come
答案
答案：C
句意：如果Bob昨天来这，他就能见到成龙了。分析句意和句子结构可知，此处表示与过去事实相反的虚拟，故从句应用过去完成时。在虚拟条件句中，如果含有had，were，should等时，if可省略，句子倒装，故此处的If Bob had come也可为Had Bob come。