1.半小时过去了，在说明时间飞逝，所以使用go by ,同时根据句子 半小时过去了可知，车从半小时到现在都没有来，所以该句时态应为一般过去式，过去完成时。
Half an hour had gone by, but the last bus had not come yet. We had to walk home.
2.这两句话为因果关系，看上去怎样使用短语seem to Marry 为单三人称，故使用seem 的三单形式,担心使用短语worry about sth.,没有背熟课文即not learn ...by heart
Marry seems to be very worried about the Chinese exam bacause she has not learned the texts by heart.
3.篮球赛已经被推迟所以使用现在完成时的被动语态has been done .不妨去做某事使用短语 might as well .
Since the basketball match has been postponed, we might as well visit the museum.
4.一直使用短语all the way ,在第二次世界大战期间使用all the way through WWII 。第二次世界大战为过去的事件，使用过去时。
He stayed in Australia with his parents all the way through the WWII.
5.自从使用since ,由此可知整句使用现在完成式，与某人失去联系使用短语lose touch with sb .
Since I graduated from Nanjing University in 1985, I have lost touch with my classmates.
