___，the compass was first made in China.A.It is known to allB.It is known thatC.We all knowD.As is known to all题中AS放在IS的前面，我是第一次看到啦，AS不是n.，本句是陈叙句，我搞不懂了，请帮我分析一下，谢谢!
热心网友
as is known 是一个固定的词组搭配，是句我所知的意思，只要记住就OK 了英语就是这样规定的。
热心网友
这是一个定语从句，As在这一句中指的就是“the compass was first made in China”