_________to all is that * is the largest island in China.

问题描述:

_________to all is that * is the largest island in China.
A.As is known B.As we know C.It is known D.What is known

选D
整个句子的结构是表语从句,is 做系动词,that 引导表语从句.所以根据主系表结构,is前面应该缺的是句子的主语.选项中只有D可以做主语,因为D是主语从句.
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