正确的应是D.
A.Could you tell me when he has been away?中when(指的是时间点)和完成时态不一起用,可改成Could you tell me when he left?或Could you tell me how long he has been away?
B.There many students want to take part in the school sports meeting.这是个中式英语句子,可改成There are many students who want to take part in the school sports meeting.或去掉there,变成Many students want to take part in the school sports meeting
C.I hope you to come here again中hope没有hope sb.to do sth的用法.可改成I wish you to come here again或I hope you can come here again
D.正确.宾语从句用一般现在时表示客观事实,虽然主句用过去时.