He _____________ back in an hour．

I ______ he'll be back in an hour.

[    ]

　　A. don't think　　 B. had thought

　　C. hadn't thought  D. think not

He will be back in _______ hour.

　　A.a　　B.an　　C.the　　D.／

He'll be back ______.

[    ]

　　A. after half a hour   B. after half an hour

　　C. in half a hour　　  D. in half an hour