21.(2008北京) — Did you return Fred’s call?
— I didn’t need to __________ I’ll see him tomorrow.
A. though B. unless C. when D. because
答案：D
解析：本题考查状语从句。从句为原因状语从句，选D，因为我明天就要看见他了，所以没必要给Fred回电话。

22.(2008北京) I’m sorry you’ve been waiting so long, but it’ll still be some time __________ Brain gets back.
A. before B. since C. till D. after
答案：A
解析：本题考查状语从句。本题使用了it will be + 一段时间 + before +状语从句，表示“在……之前还需要一段时间，一段时间之后发生某事”。后面句子的含义：不过Brain还要过一会儿才能回来。

23.(2008天津) We’ll have a picnic in the park this Sunday __________ it rains or it’s very cold.
A. since B. if C. unless D. until
答案：C
解析：考查状语从句的引导词。句意“除非太冷或天太冷，否则我们本周就到公园野餐”，unless引导一个表示否定意义的条件状语从句。

24.(2008福建) Nancy enjoyed herself so much __________ she visited her friends in Sydney last year.
A. that B. which C. when D. where
答案：C
解析：考查状语从句。根据题干意思可知，此处是时间状语从句，选C。

25.(2008全国I) — Have you got any idea for the summer vacation?
— I don’t mind where we go __________ there’s sun, sea and beach.
A. as if B. as long as C. now that D. in order that
答案：B
解析：as if表示“仿佛，好像”，引导方式状语从句，now that表示“既然”，引导原因状语从句；in order that表示“为了”，引导目的状语从句；as long as表示“只要”，引导条件状语从句。依句意可知，答话者不介意去任何地方，只要那里有阳光、大海和海滩。

26.(2008山东) He found it increasingly difficult to read, __________ his eyesight was beginning to fail.
A. though B. for C. but D. so
答案：B
解析：考查分句逻辑关系判断和连词辨析。由语境可知，后一个分句“视力开始下降”是前一个分句“读书越来越困难”的原因，所以用for引导原因状语从句。干扰性最大，但其后要跟结果状语从句，所以应该排除。Though引导让步状语从句，but引导转折关系的分句。

27.(2008辽宁) __________ hungry I am, I never seem to be able to finish off this loaf of bread.
A. Whatever B. Whenever C. Wherever D. However
答案：D
解析：hungry为形容词，whatever常用来修饰名词；依句意：无论我多么饥饿，我看起来永远也不会吃完这块面包，可知答案为D。

28.(2008辽宁) I used to love that film __________ I was a child, but I don’t feel it that way any more.
A. once B. when C. since D. although
答案：B
解析：once用作连词，表示“一旦”，引导条件状语从句；when表示“当……的时候”，常引导时间状语从句；since表示“从……以来”，引导时间状语从句，还可以表示“既然”，引导原因状语从句；although表示“尽管”，引导让步状语从句。

29.(2008四川) I haven’t seen Ann for __________ long that I’ve forgotten what she looks like.
A. such B. very C. so D. too
答案：C
解析：此处是“so … that”结构，表示“如此……以至于”。A项用来修饰名词。

30.(2008四川) There are some chairs left over __________ everyone had sat down.
A. when B. until C. that D. where
答案：A
解析：句意“当大家都就座后还剩下几把椅子”，此处强调的是时间。until用于肯定句时一般与连续性动词连用，而句子中的sat down是短暂性动词词组，因此B项不恰当；C项语法不正确；D项表示地点，不符合题意。