Nobody knows exactly how many years it will be the Chinese football team enters the final

问题补充：

Nobody knows exactly how many years it will be the Chinese football team enters the final stage of the World cup.

A. when B. for C. before d. until

答案：

解析：句意：没人能确切第知道还得有多少年中国足球对才能进入世界杯决赛。Before 与一段时间连用，意为“才，就 ”。