[例1]Roses need special care______they can live through winter.
A.because B.so that C.even if D.as
【解析】答案B。so that引导目的状语从句，“为了”。
[例2]______you call me to say you’re not coming，I’ll see you at the theatre.
A.Though B.Whether C.Until D.Unless
【解析】答案D。unless引导条件状语从句，表示“除非，如果不”。
[例3]Several weeks had gone by ______I realized the painting was missing.
A.as B.before C.since D.when
【解析】答案B。before这里表示“过了……（时间）才”，引导时间状语从句。
[例4]I do every single bit of housework______my husband Bob just does the dishes now and then.
A.since B.while C.when D.as
【解析】答案B。while表示前后对比，“然而，可是”。
[例5]Jasmine was holidaying with her family in a wildlife park______she was bitten on the leg by a lion.
A.when B.while C.since D.once
【解析】答案A。when是等立连词，表示“正在这时”。
[例6]Parents should take seriously their children’s requests for sunglasses______eye protection is necessary in sunny weather.
A.because B.through C.unless D.if
【解析】答案A。because引导原因状语从句。
[例7]It was evening______we reached the little town of Winchester.
A.that B.until C.since D.before
【解析】答案D。before引导时间状语从句，表示“在……之前”。
[例8]You can eat food free in my restaurant______you like.
A.whenever B.wherever C.whatever D.however
【解析】答案A。whenever引导让步状语从句，意为“无论何时”。
[例9]It was______back home after the experiment.
A.not until midnight did he go
B.until midnight that he didn’t go
C.not until midnight that he went
D.until midnight when he didn’t go
【解析】答案C。这是“It was not until…that…”引起的强调句型。