as_if__用法解析(课堂PPT)

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as if 用法解析
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as if 从句的语气及时态 1． as if 从句用陈述语气的情况。 当说话者认为句子所述的是真实的或 极有可能发生或存在的事实时。如： 1） It sounds as if it is raining． 听起来像是在下雨。
2） He talks as if he is drunk． 从他谈话的样子来看他是醉了。
(snoቤተ መጻሕፍቲ ባይዱ)．
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as if 的省略情况
• 当as if/ though 从句中的主语 与主句中的主语一致时，可以省略 as if 从句中的主语（和be动词）， 情况如下：
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as if + 形容词
1. He lay still for a long while as if (he were) dead.
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2．as if 从句用虚拟语气的情况。
当说话人认为句子所述的是不真实 的或极少有可能发生或存在的情况 时。从句虚拟语气动词时态的形式 如下：
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• 1）如果从句表示与现在事实相反， 谓语动词用一般过去时。如：
1）You look as if you didn’t care． 你看上去好像并不在乎。
2. He left the room hurriedly, as if (he was) angry.
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as if + 名词 e.g. He acts as if (he were)
a fool.
as if +介词短语 e.g. He looked about as if (he
was) in search of something.
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as if + to do 1) He raised his hand as if (he was going) to say something. 2) He opened his lips as if (he were) to make some reply.
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as if + 现在分词（doing）
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If you go to the Science Museum ， you (see) a lot of interesting exhibitions.
If people don't stop polluting the air，animals
and plants
soon (die).
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2．非真实条件句(虚拟条件句)
条件句
1．真实条件句 有些条件句表示可能成为现实的情况，被称为真 实条件句。真实条件句的构成和用法如下： (1)由“if引导的条件状语从句(一般现在时)＋主句(陈述 句一般将来时)”构成，表示假设的情况有可能发生。 If the rain stops，the match will begin. 如果雨停了，就要开始比赛。
2）You look as if you a ghost.
(see)
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（3）从句表示与将来事实相反，谓语动 词用“would／could／might＋动词原 形”。如：
1)He opened his mouth as if he (say) something．
他张开嘴好像要说什么。
2) It looks as if it 看来好像要下雪了。
例句： If I were you，I
(invite) him to the party.
If she were younger，she science.
(study) computer
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①过去式（be动词用were） ②should/were to +动词 原形
should/would/could/mig ht＋动词原形
有些条件句表示不大可能实现的或与事实相反的情况， 被称为非真实条件句.
had＋过 should/would/could/
去分词
might＋动词原形
If they had invited her，she
(attend) it.
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过去式（be 动词用were）
should/would/could/mi ght＋动词原形
2） He talks as if he
(know) where
she was．
他说话的样子，好像他知道她在哪里似的。
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（2）从句表示与过去事实相反， 谓语动词用“had＋过去分词”。 如：
1) He talks about Rome as if he (be) there before．
他说起罗马来好像他以前去过罗马似的。
Lhasa instead of flying last summer.
(2012·陕西)
A．was
B．had been
C．should be
D．would be
解析 句意：如果我的车更加可靠的话，去年夏天我就开车
去拉萨而不乘飞机啦。本题考查虚拟语气。if从句与过去事 实相反，故应用过去完成时。
答案 B
1) From time to time Jack turned round as if (he was) searching for someone 2) He paused as if expecting Mary to speak.
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• If I were you, I would go with them. = Were I you,
If it should rain tomorrow, I would stay at home. = Should it rain tomorrow,
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语法专练
1．If my car________more reliable，I would have driven to
例句：
If we should fail in this matter，we
(ruin).
If it rained/should rain/were to rain tomorrow, I home.
(stay)at
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• 如果从句中有should，were或had的时候，可以 省略if，把should，were或had提到主语之前， 构成倒装。