— Did he realize the serious situation immediately?— No. It was quite a long time he real

问题补充：

— Did he realize the serious situation immediately?

— No. It was quite a long time he really realized it.

A. now that

B. when

C. ever since

D. before

答案：

A. now that

B. when

C. ever since

(答案→)D. before

解析：连词辨析。A.既然；由于 B.当……时C. 从那时到现在 D. 在……之前。句意：他理解意识到了这严重的情况吗？——不，在他真正意识到它之前，有相当长一段时间。故选D。