(3)你来这儿多久了？“我来这儿一个小时了。（4）我还没有完成作业呢？（5）他刚刚来。怎么翻译

How long have you come here? "I came here an hour. (4) I have not yet completed exercise books? (5) he had just come.

3.How long have you been here? (I have been here ) one hour.
4.I haven't finished my homework yet. 为什么是问句?
5.He had just come。