成人英语三级考试

【单选题】______ the compass was first made in China.
A．It is known to all
B．It is known that
C．We all know
D．As is known to all

网考网参考答案：D
网考网解析：
本题考查的是固定结构as is known to all，即众所周知。因为这是非限定性定语从句，所以与主句用逗号隔开。而若用 it is known to all，则是 it 做形式主语的情况，后面直接加 that，不用标点符号，故排除A，D. 查看试题解析出处>>