1.A half hour had goes by,but the last bus hasn't come. We had to go home on foot.

半小时过去了，表是已经过去，用一般过去形式，但……转折，只好用不得不have to表示，因为现在已经到家，这事过去时态，用had to

2.Mary seems to be worried about the Chinese exam,because she has't learnd passage by heart.

玛丽看上去对……担心，译为，看起来伤心，再写为何。玛丽是第三人其后谓语动词用三单形式。

3.Now that the basketball game has been postponed ,we might as well visit the museum.

既然已经完成，这是过去完成时态用has been down.不妨是短语might as well.

4.During the World Wars‖,he staied in Austrolla with his parents all the way.

在……期间用during﹉时间段﹉，他定居和他的父母一直。状语后置。

5.Since I graduated from Nanjing University in1985,I kind of lose touch  with my university classmates.

自从我在1985年从南京大学毕业，时间状语后置，失去联系lose touch with.