目的状语从句的用法

　　目的状语从句可以由表示“为了， 以便”的so that(有时省略so)， in order that和表示“以免， 以防”的lest， for fear that， in case引导(lest， for fear that后的目的状语从句一般要用“可以省略的should＋动词原形”的虚拟语气形式； in case后的目的状语从句多用虚拟语气， 但也可用陈述语气)。例如：

They set out early that they might arrive in time. 他们早点动身， 以便及时到达。

She takes notes carefully in class so that she may use them when she reviews her lessons after class. 她在课堂上认真记笔记， 以便她能在课后很好地复习功课。

He shouted at the top of his voice in order that he might be heard. 他尽力大声叫喊， 以便别人能听见。

 I will not make a noise lest I (should) disturb you. 我不出声， 以免打搅你。

He is working hard for fear that he (should) fail. 他认真学习， 以免考不及格。

Take your umbrella in case it rains. 带上雨伞， 以防下雨。

        如果表示“为了， 以便”的目的状语从句的主语与主句的主语相同， 可用in order to或 so as to取代该目的状语从句， 注意体会以下例句：

He hurried through his work in order to catch the train. 他匆匆干完手中的活， 为的是能赶上火车。

 I sent the plans in order for you to study them fully before the meeting. 我寄上这些计划以使你会前充分研究一下。 

 The desks are kept some distance apart, so as to prevent cheating. 这些书桌都隔着一段距离摆放， 以防作弊。 

 I came so early as to catch the first train. 我起得早， 以便能赶上头班火车。

［考题1］ I’d like to arrive 20 minutes early ____ I can have time for a cup of tea.

　　A. as soon as       B. as a result

        C. in case             D. so that

［答案］ D

　　［解析］ so that表示希望实现的目的。

　　［考题2］ Roses need special care ____ they can live through winter.

　　A. because B. so that C. even if D. as

［答案］ B

　　［解析］ so that表示希望实现的目的。

　　［考题3］ Leave your key with a neighbor ____ you lock yourself out one day.

　　A. ever since       B. even if

        C. soon after      D. in case

［答案］ D

　　［解析］ “you lock yourself out one day”是应该避免出现的结果， 下划线处应选用in case， 引导目的状语从句, 表示“以免……”。

　　［考题4］ I shall stay in the hotel all day ____ there is news of the missing child.

　　A.in case            B.no matter

       C.in any case     D.ever since

［答案］ A

　　［解析］ 题干意为： 我将整天在旅店里呆着， 以防有丢失孩子的消息。本题应选in case引导目的状语从句表示“以防……”。