It’s quite a time Liu Xiang was injured in the foot but we are sure it won’t be long he

问题补充：

It’s quite a time Liu Xiang was injured in the foot, but we are sure it won’t be long he returns to the track.

A. after; when

B. before; since

C. that; when

D. since; before

答案：

A. after; when

B. before; since

C. that; when

(答案→)D. since; before

解析：考查连词用法。句意：自从刘翔在脚部受伤以来有相当一段时间了，但是我们确信不久他就会回到跑道。根据语意应选D。