Question

表语从句是什么？表语又是什么

Answer 1

主系表结构中的表语常放在系动词后，用来描述主语的身份、外表或心理特征。如She is a girl. she looks beautiful.等中的a girl和beautiful都叫表语。表语从句指用一个完整句作表语，如My suggestion is that you should go over your lesson in time .中的that从句及表语从句。
常见系动词有be, look,smell,feel等。