10、注意状语从句中从句的省略现象(1)连接词 过去分词Don’t speak until spoken to.Pressure can be incrased when needed.Unless repaired， the washing machine is no use.(2)连词 现在分词Look out while crossing the street.(3)连词 形容词/其他常见的有it necessary、if possible、when necessary、if any等。
二、精典名题导解
选择填空
1. I don’t think I’ll need any money but I’ll bring some ____________。
A.as last
B.in case
C.once again
D.in time
解析：答案为B.句意为“带些钱以防万一”，只能选择in case.引导的条件状语从句，后面省略了I should need it.
2. The WTO can’t live up to its name _________ it doesn’t include a country that is home to one fifth of man-kind.
A.as long as
B.while
C.if
D.even though
解析：答案为C.本题考查状语从句的用法。句意为“假如世贸组织不包括占世界人口五分之一的中国的话，那它就名不副实”。as long as语气过于强烈，while和even though不符合句意。
3、Someone called me up in the middle of the night， but they hung up_________I could answer the phone.
A.as
B.since
C.before
D.until
解析：答案为C.题意为：半夜里有人打来电话，我没来得及就挂了。but暗示在接话前就挂了。