分类：教育/科学-学习帮助
问题：单项选择5.whenireachedthestation,ire 
5.when i reach the station, i realized i __________ my ticket at home.a. left b. had left c. forgot d. had forgot
回答：选B。
这里要用过去完成时，因为忘记车票是发生在到车站之前的事。