-----is known to all is that the Diaoyu Islands have belonged to China since ancient times.A.As B.It C.What D.That
问题描述：
-----is known to all is that the Diaoyu Islands have belonged to China since ancient times.A.As B.It C.What D.That
答
C what is known to all是主语从句,整个做主语,横线部分少从句的主语,所以用疑问代词what