China's success in manned－spacecraft travel shows our country has bee one of the greatest powers in space research.
A. what
B. which
C. /
D. it that
网友回答
A. what
B. which
(答案→)C. /
D. it that
解析：该句中的从句作shows的宾语，是宾语从句，又因为从句中不缺主、宾语，所以只能用that引导；又因引导宾语从句时that可以省略，所以答案是C。