复合句(Complex Sentence)一个主句和一个以上的从句所构成的句子称为复合句，也称为主从复合句。

复合句通常由关联词把主句和从句连接起来。例句： Other models exist that are hybrids of these three, such as delayed open access, where journals allow only subscribers to read a paper for the first six months before making it freely available to everyone who wishes to see it. (选自2008年Text 2)