复合句【语法要点】复合句是由一个主句加一个或几个从句所构成的句子。从句只用作句子的一个成分，不能独立。根据从句在句子中的作用，可分为名词性从句、定语从句和状语从句三类。（一）名词性从句名词性从句包括主语从句、表语从句、宾语从句、同位语从句。其关联词有连接词that、if、whether；疑问代词who、what、which和疑问副词when、where、how、why等。1.名词性从句句法结构：从属连词thatwhether主语从句That he will come is certain.（that不可省）Whether she is coming or not doesnt matter too much.（不能用if）宾语从句I think（that）he will be all right in a few days.I went in and asked if（=whether）they had a cheap suit.I wonder whether（不能用if）it is
