________, a good effort has been made by the Chinese Government to control the spreading of Sars.
A.As is known to all
B.It is known to all that
C.Which is known to all
D.We all know that
网友回答
A解析导解:as we know或as is known to all其后有一逗号,这是as引导非限定性定语从句的用法.