原因状语从句-(最新版）.pdfVIP

二、原因状语从句： 1、定义：在句中用来说明主句原因的句子叫原因状语从句。 2、常用引导词:because (因 ), as ( 由于), since (既然), now (that) (既然) 3、时态：原因状语从句一般都是根据实际情况选用适当的时态。通常是主过从过， 主现从现。 4、because, since 和 as 的区别： 1) because 引导的原因状语从句一般放于主句的后面，because 从句位于句首时 要用逗号分开，放在句末时，可不用逗号分开。because 表示直接原因， 语气最强， 最 适合回答 why 引导的疑问句。because of 也表示原因，但它后面不接从句, 只能接名词, 代词或动名词。注意：because 和 so 不可同时出现在一个句子里。 ① I do it because I like it. = I like it so I do it. ② We went by bus because it was cheaper. = It was cheaper so we went by bus. ③ He can’t go to school because of his illness. 2) since 引导的原因状语从句一般放于主句之前表示已知的、 显然的理由(通常被 翻译成“既然”= now that )， 较为正式， 语气比 because 弱。 ① Since you are free today, you had better help me with my mathematics. ② Since you don't trust him, you should not employ him. ③ Now (that) you are grown up, you should not rely on your parents. 3) as 引导原因状语从句时表示附带说明的“双方已知的原因”，含有对比说明的意味， 语气比 since 弱， 较为正式， 位置较为灵活(常放于主句之前)。 ① As it is raining, you’d better take a taxi. ② As you are tired, you had better rest. ③ I went to bed early, as I was exhausted. 4) for 引导的是并列句表示原因但并不说明主句行为发生的直接原因， 只提供一些 辅助性的补充说明， for 引导的并列句只能放于主句之后并且必须用逗号将其与主句隔 开。 ① He could not have seen me, for I was not there. ② He seldom goes out now, for he is very old. 5. 三、目的状语从句： 1、定义：在句中用来作目的状语的句子叫目的状语从句。 2、常用引导词: so that (以便), in order that (以便) 3、时态：目的状语从句一般都是根据实际情况选用适当的时态。也通常是主过 从过，主现从现。 4、目的状语从句应注意以下： 1) 目的状语从句中常含有can, could, may, might, should, will, would 等情态动词。 I got up early so that I could catch the first bus. 2) 在口语中 so 可以引导目的状语从句。 We'll sit nearer the front so we can hear better. 3) in order that 与 in order to 的区别： ① in order that +从句 = so that +从句 ② in order to+ 动词原形 = so as to + 动词原形(不放于句首) = to+ 动词原 形 I get up early in order to catch th