I'm very glad to see you.I ( ) you had come already.A.don't know B.haven't know C.didn't know D.hadn't know选什么?为什么?

I'm very glad to see you.I ( ) you had come already.A.don't know B.haven't know C.didn't know D.hadn't know选什么?为什么?
I'm very glad to see you.I ( ) you had come already.
A.don't know B.haven't know C.didn't know D.hadn't know
选什么?
为什么?

I'm very glad to see you.I ( ) you had come already.A.don't know B.haven't know C.didn't know D.hadn't know选什么?为什么?
c
had come过去完成时 前面就该用一般过去时

选C
后面是HAD COME，所以前面一定是过去时态，而且不可能两个完成时一起用，所以选C．