分类：教育/科学-外语学习
问题：keepdoingWhatmadeBillsoangry?___ 
What made Bill so angry?________.His girl friend mised to come at 8:30,but she hasn'tcome yet.AHaving kept waiting  B.Being kept waiting   be deeping wait D.Being kept waited选Ｂ．why?
回答：被动语态，因为Bill的女朋友没来，他才被迫等待的，故不能用主动语态
被动语态构成是：be（相应时态）+过去分词
keep的过去分词是kept，句型是keep doing sth
然后动名词作主语
故选B