表语从句
S+V+C(主+系+表）
结构
表语从句是指跟在系动词后面成份，
说明主语 状态、内容、特征、身份等。
1.The fact is that he didn't even read it.2.The difficulty is how I can transfer this patient to hospital.
表语是指跟在系动词后面成份，
说明主语 状态、特征、身份等。
可当表语有形容词、名词、分词、介词短语
能够接表语从句系动词有：1：表存在：be（being, been, am, is, are, was, were) appear2: 感官动词：   feel , seem , look, ,sound, taste , smell 3: 表连续：  stand , lie , remain ,keep, stay4: 表改变：become, get, grow, turn, go, come, run, fall, prove, turn out