在通常情况下，状语从句是修饰主语谓语动词的。如：

I always roll my clothes when I pack. 

我收拾行李时，总是把衣物卷成一卷。

He waved me away when I offered to help. 

我提出要帮助他时，他摆手让我走开。

如果主句有非谓语动词，状语从句好像也是修饰主语的谓语动词，而不是非谓语动词。

如：

Don’t forget to take your bag when you go. 

走的时候别忘了拿上你的袋子。

She began to grow alarmed when she realized how late it was. 

她意识到已经太晚了，就开始惊慌失措。

我想知道：状语从句可以修饰主句的非谓语动词吗？若可以，请举例说明，谢谢！

解答如下：

状语可以修饰谓语动词，也可以修饰非谓语动词，但是状语从句通常只修饰主句的谓语动词，一般不修饰非谓语动词,但是特殊情况下可以，不过不常见。

(1)时间状语从句，用来修饰/描述主句动作发生的时间。

I went to Beijing when I was twenty years old.

(2)地点状语从句，用来修饰/描述主句动作发生的地点。

We should go where we are needed most.

(3)条件状语从句，用来修饰/描述主动动作发生的条件。

If weather permits, we will have a picnic tomorrow.

(4)原因状语从句，用来描述主句动作发生原因。

Because Tom was ill, he didn't go to school.

(5)结果状语状语从句，用来说明主动动作发生的结果。

She is such a kind girl that we all like her.

(6)目的状语从句，用来说明主句动作发生的目的。

He got up so early that he could catch the first bus.

(7)让步状语从句，用来描述主动动作发生的让步。

Although he is a small boy, he knows a lot.

(8)比较状语从句，用来说明主动动作发生比较。

Tom is taller than any other boy in his class

(9)方式状语从句，用来描述主动动作发生的方式。

We should do as the teacher told us .

状语从句修饰非谓语动词特殊情况下：

Special situations where adverbial clauses can modify non-predicate verbs are as folows:

He came out of the classroom ,looking sad as if he had failed to pass the exam.

他走出教室，看起来很伤心似乎考试没有及格。

He was told to run faster so that he could catch the bus 

人家告诉他要跑快点以便能赶上巴士.

Not knowing what he should do when he was asked a question, He felt very nervous.

当他被问到一个问题却不知道怎么做，他感觉很紧张。