—How long will it be the 30th Olympic Games is held in London? —It won’t be two years I

问题补充：

—How long will it be the 30th Olympic Games is held in London?

—It won’t be two years, I think.

A. when

B. that

C. before

D. since

答案：

A. when

B. that

(答案→)C. before

D. since

解析：考查句型It will be long before... 要过很久才……。句意：要过多久伦敦才举行第三十届奥运会？ 我想不到两年。