As it is so vital a decision.I have many facts to chew upon I make up my mind．( )A．whenB．whileC．beforeD．until 题目和参考答案——青夏教育精英家教网——

题目内容

18．As it is so vital a decision，I have many facts to chew upon I make up my mind．（　　）

A．

when

B．

while

C．

before

D．

until

分析因为这是一个至关重要的决定，所以在做决定前我要好好考虑诸多实际情况．

解答答案：C
句意表达的是时间状语从句；when当…时候，while在…期间，before之前，until直到；句意表达的考虑实际情况是发生在做决定之前，故选C．

点评从属连词是连词的一种，用来引导名词性从句和状语从句．大致可分为三大类：that （无词义，不做成分）if，whether （表达是否的意义，但不做句子成分）；连接代词：who，whom，whose，what，which，whatever，whoever，whichever（有词义，在句子中可作主语、表语、宾语）；连接副词：when，where，why，how，how many，how long，how far，however，whenever，wherever （有词义，作从句的状语）．

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