________ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.
A.To waitB.Have waitedC.Having waitedD.To have waited在线课程C
解析：
本题考查非谓语动词作状语。先排除B项，因为B项是谓语动词形式，不可作状语；
A、D两项为不定式形式放在句首时常作目的状语，这显然与本题逻辑上不符。