⑴Half an hour went by, but the last bus has not come. We have to walk to home.
时态用一般过去时“went by ”,“只好”翻译为“have to do sth ”不得不。
⑵Mary seems to be worried about the Chinese exam because she has not learn text by heart.
“对...担心”翻译为“be worry about ” “because ”后加句子
⑶Since the basketball game has been postponed, we can visit the museum.
时态用现在完成时的被动“has . been postponed ”，不妨翻译为“can ”
⑷All the way during the World War two, he has lived with his parents in Australia.
因为是二战期间，所以用现在完成时。句子主干是他和父母住在澳大利亚。
⑸Since I graduated form NanJing university in 1985 , I can say that I have kind of lost touch with my college classmates.
“Since”主句用一般过去时，从句用一般现在时。句子主干是我和同学失去联系。
