2014高考英语二轮语法连词讲解及试题集_高考语法

2014高考英语二轮语法连词讲解及试题集

　　4、because, since, as引导原因状语时注意使用上的区别：

　　①如果原因构成句子的最主要部分,一般用because ,因此because引导的从句往往放在句末。用why提问的句子，一定用because回答。例如：He had to stay at home yesterday because he was ill.；

　　②如原因已为人们所知，或不如句子的其他部分重要，就用as，或 since。since比as更正式些。as和since引导的从句一般放在句子的开头。例如：As you are tired, you had better rest./ Since everyone is here, now lets begin.

　　5、although和though引导让步状语从句往往用法一样，但注意以下区别：

　　①although用于各种文体，而though则多用于非正式的口语或书面语中。注意由although, though引导的从句后，主句不能用but，但可用副词yet, still。例如：Although/ Though it rained all the morning, they still went on working.（或yet they went on working）

　　②though常与even连用，even though表示强调，意为即使，但不能说even although，例如：Even though I didnt understand a word, I dept smiling.

　　③though可用作副词，意为然而，常用逗号与句子分开。although则不能这样使用，它只作连词。例如：It was a quiet party, I had a good time, though. 6、once作副词译曾经，作为连词译一旦，引导条件状语从句。相当于if的加强形式。例如：I dont believe he was once a thief. (once这里是副词)/ Once Aristotle had made up his mind that heavy objects always fell faster than light objects, he taught it as a truth to his students. (once连词)