He didn't realize he had forgot his bag the plane had taken off. A. unless B. until C. if

问题补充：

He didn realize he had forgot his bag the plane had taken off.

A. unless

B. until

C. if

D. or

答案：

A. unless

B. until

C. if

D. or

解析：考查连词辨析。此处为直到---才---的意思，故选B符合。