语法点:目的状语 so that / in case / to (Purpose Clauses)
要说明"为了什么"而做某事,英语有几种办法。最简单的是动词不定式 to do(正式一点用 in order to / so as to)。如果目的部分有自己的主语,就要用从句:so that + 主语 + can / could / should / will / would + 动词。in case 的意思是"以防万一",说明为了防备某种可能而事先采取行动,从句用一般现在时或一般过去时,不用 will。本课演员们"采取特别措施 so that 没人认出他们",警长说"in case 你们不识字"——这些都是典型的目的表达。
结构
| 形式 | 结构 | 例句 |
|---|---|---|
| 不定式 | to / in order to / so as to + 动词原形 | They wore dark glasses to hide their faces. |
| 否定不定式 | in order not to / so as not to + 动词原形 | They wore old clothes so as not to be recognized. |
| so that 从句 | so that + 主语 + can / could / should / would + 动词 | They took precautions so that no one should recognize them. |
| in case 从句 | in case + 主语 + 一般现在 / 过去时 | It says 'No Camping' in case you can't read. |
要点:1) so that 从句里常用情态动词,主句过去时则用 could / should / would;2) in case 后面不用 will;3) 不定式的逻辑主语必须与主句主语一致。
课文中的例句
- [句 2] …they had taken special precautions so that no one should recognize them. — so that + should 说明采取措施的目的
- [句 11] It says 'No Camping' -- in case you can't read! — in case 表示"以防你们不识字"
- [句 7] …had carried two large food baskets to a shady spot under some trees. — 把篮子搬到树荫下,目的是野餐(隐含目的)
- [句 3] But as they soon discovered, disguises can sometimes be too perfect. — 化装的目的达到了,却带来意外后果
补充例句
- The actors got off the bus early so that no one would see them. — 演员们提前下车,这样就没人看见他们。
- Take a coat with you in case it gets cold. — 带件外套,以防天冷。
- She wore dark glasses so as not to be recognized by film fans. — 她戴上墨镜,以免被影迷认出来。
易错点
- ❌ They took precautions so that no one recognize them. → ✅ They took precautions so that no one should recognize them. — so that 从句里要有情态动词或完整的谓语。
- ❌ It says 'No Camping' in case you will not be able to read. → ✅ It says 'No Camping' in case you can't read. — in case 后不用 will。
- ❌ They wore old clothes for not to be recognized. → ✅ They wore old clothes so as not to be recognized. — 否定目的用 so as not to / in order not to。
- ❌ They came here for having a picnic. → ✅ They came here to have a picnic. — 表目的直接用 to do,不用 for + 动名词。