【题目】 He is disappointed. He appears ____ what has happened to his competition.
A. knowing B. to know
C. having known D. to have known
在线课程【答案】D
【解析】
试题分析：考查动词的用法。句意：他很失望，他好象已经知道比赛中发生的事情； appear to do 好象做某事，根据what has happened to his competition可知事情已经发生，故用appear to have done，因此选D项；
考点 : 考查动词的用法