_____is known to all,China will be a powerful country in the 21st century.

问题描述:

_____is known to all,China will be a powerful country in the 21st century.
A That B As C This D Which 为什么呢 为什么不选别的

首先句子中有个逗号,意味着这只是一个句子,所有的语言都是以句号为一句话的.选项只能选连词构成从句.
如果选AC就构成了两个句子,中间不能用逗号.
BD是连词,可以用来引导从句.which引导从句不能用于句首.