连接词主要有if,unless,as/solongas,onconditionthat等。.
if引导的条件句有真实条件句和非真实条件句两种。非真实条件句已在虚拟语气中阐述。 unless=ifnot.
Let'sgooutforawalkunlessyouaretootired.
Ifyouarenottootied,let'sgooutforawalk.典型例题
Youwillbelate___youleaveimmediately.
A.unless B.until C.if D.or
答案A。句意：除非你立即走，否则你就回迟到的。可转化为Ifyoudongleaveimmediately,youwillbelate. B、D句意不对，or表转折，句子如为Youleaveimmediatelyoryouwillbelate.
