请问这个句子是主语从句还是表语从句，怎么看

显示全部楼层 · 2008-7-7 11:42:44

What is even important is that as the earth cooled down,water began to appear on its surface.

千问 · 2008-7-7 11:42:44

既有主语从句，也有表语从句。如果把What is even important比作A把that as the earth cooled down,water began to appear on its surface比做B则还原为 Ais B这样A就是主语，又是从句，所以就是主语从句is 后面的从句就是表语从句符合句型“主+系+表”

千问 · 2008-7-7 11:42:44

What is even important 是主语从句that as the earth cooled down,water began to appear on its surface. 作表语从句整个句子是主系表结构更重要的是，随着地面温度下降/逐渐冷却，水开始渗出地表。