2022年高考英语人教版第二轮复习知识点精讲11并列句和状语从句(四).docx
三、原因状语从句 原因状语从句是表示原因和理由的从句。引导原因状语从句的有as, because, since, now (that), considering that, seeing that等。 （一）Because Because I like it, I do it.因为我喜欢，所以我才干。 He couldnt have seen me, because I was not there.他不可能见过我，因为当时我不在那儿。 比较： because 和for的区别： for 是并列连词，只用于连接表示原因的分句，因此不能用于句首。because表示原因时，可位于句首。 【误】For he did not obey the rules, he was punished. 【正】Because he did not obey the rules, he was punished. 由于他不遵守规章制度，他受到了处。 for 表示的是推断解释，because强调动作发生的直接原因。 It must have rained last night, for the ground is wet. 昨晚肯定下雨了，因为地面是湿的。（不可用because，因为地面湿不是天下雨的原因） The day breaks, for the birds are singing. 天亮了，因为鸟在叫。（不可用because，因为鸟叫不是天亮的原因） He went to bed early, because he was tired 由于他累了，所以他很早就上了床。（直接的理由） He must be tired, for he went to bed early. 他肯定累了，因为他很早就上了床。（间接的推断） 在强调结构It is/was.that和关联词notbut 引导的原因状语从句中，宜用because。 It's because he helped you that I'm prepared to help him. 正是因为他帮助过你，所以我乐意去帮助他。 He decided to give up the chance of going abroad, not because he did not want to but because his wife was ill. 他 决定放弃出国的机会，不是因为他不想去，而是因为他妻子病了。 （二）since， as since 因为，既然。引导的从句大多置于句首，主从句的时态一般相同。as 由于。一般多用于句首。 Since you have no licence, you are not allowed to drive.因为你没有驾驶执照，所以不允许你开车。 Since you are al here, let's try and reach a decision.既然大家都来了，咱们就设法做出一个决定吧。 As she was ill, she didn't come to the party.由于病了，她没来参加晚会。 As he was not well enough, I had to go without him.由于他身体欠佳，我只好不带他去了。 As it rained, we all stayed at home.由于下雨我们都呆在家里。 【易混辨析】because, since, as because语气最强，表达的是未知的新信息，一般置于主句之后，也可以放在主句之前，用逗号隔开。在 回答why引导的特殊疑问句时，或在强调结构It is/was .that 和关联词not .but 引导的原因状语从句中， 要用because。另外，because还常和副词just, merely等连用。 since 表示的是已知的客观事实或分析后的推理，引导的从句大多置于句首，主从句的时态一般相同。 as 表示的理由最弱，只是对主句的附带说明，重点在主句。as从句通常放在主句前。 Just because he doesn't complain, you must not suppose that he is satisfied. 你不可只因他不抱怨就以为他满足了。 You shouldn't get angry only because some people speak ill of you. 你不该仅仅因为有些人说了你的坏话就生气。 Since you're not interested, Iwon't tell you about it.既然你不感兴趣，那我就不告诉你了。 As you are unable to answer perhaps we should ask someone else. 因为你不能回答，也许我们该问一问别的人。 注意：because等词不能与 so连用。 （三）now that now that 既然，因为。that可以省略。 Now (that) dinner is ready, go and wash your hands.既然饭已好了，洗手去吧。
