(·皖南八校联考) here yesterday he could have seen Jackie Chan.A. If Bob has come　　B. If Bob

问题补充：

(·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：

A. If Bob has come

B. If Bob came

(答案→)C. If Bob had come

D. If Bob should come

解析：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。