一、目的状语从句的定义
目的状语从句是复合句中的一种从句，用于说明主句动作或状态的目的。它通常由特定的连接词引导，这些连接词将从句与主句紧密联系起来，表达“为了……”的含义。
 
二、目的状语从句的连接词
目的状语从句的连接词是引导从句的关键，常见的连接词包括以下几种：
 
1. so that
用法：表示“为了……”或“以便……”，是最常用的目的状语从句连接词。
结构：
主句 + so that + 从句（从句中常用 can/could/may/might/will/would 等情态动词）
例句：
He worked hard so that he could pass the exam.（他努力学习，以便通过考试。）
She saved money so that she could buy a new car.（她攒钱是为了买一辆新车。）
 
2. in order that
用法：表示“为了……”，与“so that”意思相近，但语气稍强。
结构：
主句 + in order that + 从句（从句中常用 can/could/may/might/will/would 等情态动词）
例句：
He stayed up late in order that he could finish his report.（他熬夜是为了完成报告。）
She studied hard in order that she could get a good grade.（她努力学习，以便取得好成绩。）
 
3. in order to
用法：表示“为了……”，是“in order that”的简化形式，后面直接接动词原形。
结构：
主句 + in order to + 动词原形
例句：
He stayed up late in order to finish his report.（他熬夜是为了完成报告。）
She studied hard in order to get a good grade.（她努力学习，以便取得好成绩。）
 
4. so as to
用法：表示“为了……”，与“in order to”意思相近，但语气稍弱。
结构：
主句 + so as to + 动词原形（注意：so as to 不能用于句首）
例句：
He worked hard so as to pass the exam.（他努力学习，以便通过考试。）
She saved money so as to buy a new car.（她攒钱是为了买一辆新车。）
 
5. for fear that
用法：表示“以免……”或“生怕……”，常用于表示担心或预防某种结果。
结构：
主句 + for fear that + 从句（从句中常用 should/would 等情态动词）
例句：
He took his umbrella for fear that it should rain.（他带了伞，以防下雨。）
She spoke softly for fear that she should wake him up.（她小声说话，以免吵醒他。）
 
6. lest
用法：表示“以免……”，用于表示担心或预防某种结果。
结构：
主句 + lest + 从句（从句中常用 should 等情态动词）
例句：
He took his umbrella lest it should rain.（他带了伞，以防下雨。）
She spoke softly lest she should wake him up.（她小声说话，以免吵醒他。）
 
三、目的状语从句的注意事项
so that 和 in order that 的区别
so that 和 in order that 都表示“为了……”，但 in order that 语气稍强，且可以用于句首，而 so that 不能用于句首。
例句：
He worked hard so that he could pass the exam.（他努力学习，以便通过考试。）
In order that he could pass the exam, he worked hard.（为了通过考试，他努力学习。）
in order to 和 so as to 的区别
in order to 和 so as to 都表示“为了……”，但 in order to 可以用于句首，而 so as to 不能用于句首。
例句：
He worked hard so as to pass the exam.（他努力学习，以便通过考试。）
In order to pass the exam, he worked hard.（为了通过考试，他努力学习。）
for fear that 和 lest 的区别
for fear that 和 lest 都表示“以免……”，但 for fear that 更常用于表示担心，而 lest 更常用于表示预防。
例句：
He took his umbrella for fear that it should rain.（他带了伞，以防下雨。）
He took his umbrella lest it should rain.（他带了伞，以防下雨。）
 
四、目的状语从句的练习
He worked hard ________ he could pass the exam.
A. so that
B. in order that
C. in order to
D. so as to
答案：A 或 B（表示“为了……”，用 so that 或 in order that。）
He took his umbrella ________ it should rain.
A. for fear that
B. lest
C. so that
D. in order to
答案：A 或 B（表示“以防……”，用 for fear that 或 lest。）
She studied hard ________ get a good grade.
A. so that
B. in order to
C. so as to
D. in order that
答案：B 或 C（表示“为了……”，用 in order to 或 so as to。）
He spoke softly ________ he should wake her up.
A. for fear that
B. lest
C. so that
D. in order to
答案：A 或 B（表示“以免……”，用 for fear that 或 lest。）
__________ he could pass the exam, he worked hard.
A. So that
B. In order that
C. In order to
D. So as to
答案：C（表示“为了……”，用 in order to，且可以用于句首。）
 
五、总结
目的状语从句是复合句中用于说明主句动作或状态目的的重要从句类型。掌握常见目的状语从句的连接词（如 so that, in order that, in order to, so as to, for fear that, lest 等）及其用法，可以帮助你更清晰地表达目的关系。同时，注意区分不同连接词的用法和语气，以及它们在句中的位置。希望这篇文章能帮助你更好地理解和运用目的状语从句。