2024年初中英语语法：部分从属连词用法
从属连词when/after/before在引导状语从句时应该怎么用?
when before after 从属连词定义
用来连接两个子句：引导状语从句，连接主句。
状语从句必须依附主句，不能单独存在。
状语从句在前，主句在后，两个句子中间必须加上逗号。
When 用法（当...的时候）
主句+when+状语从句 = When+状语从句，主句
When she has money, she likes to buy books.
当她有钱的时候，她喜欢买书。
I said hi to him when I saw him.
= When I saw him, I said hi to him.
当我看见他的时候，我对他说了声嗨。
表示现在的习惯或状态
主句(现在式)+ when + 状语从句(现在式)
Peter likes to go jogging when he is free.
当Peter有空的时候，他喜欢去慢跑。
表示未来会发生的事
主句(未来式/祈使句)+ when +状语从句(现在式)
I will give you a gift when you come here tomorrow.
当你明天来的时候，我将会给你一个礼物。
Be careful when you walk on the street at night.
当你夜晚走在街头的时候，要小心。
表示过去发生的事情
主句(过去式)+ when + 状语从句(过去式)
Sam went outside when he heard Tina screaming.
当Sam听到Tina尖叫时，他跑到外面去。
My mom was cooking dinner when Vivian rang the doorbell.
当Vivian按门铃时，我妈妈在煮晚餐。
after（在.…..之后）/ before（在.…..之前）用法
主句+after/before+状语从句
= After/Before+状语从句，主句
After he eats breakfast, he goes to work.
在他吃早餐之后，他去上班。
表示现在的习惯或状态
主句(现在式)+ after/before + 状语从句(现在式)
He watches TV after he finishes his work every night.
= After he finishes his work every night, he watches TV.
每天晚上，在他完成工作之后，他会看电视。
She brushes her teeth before she goes to bed.
= Before she goes to bed, she brushes her teeth.
她在上床睡觉之前会刷牙。
表示未来会发生的事
主句(未来式/祈使句)+ after/before +状语从句(现在式)
I will give you a gift after you come here tomorrow.
在你明天来后，我将会给你一个礼物。
Before you have dinner, wash your hands.
在你吃晚餐前，先洗洗手。
表示过去发生的事
主句(过去式)+ after/before +状语从句(过去式)
Tony had a big dinner with his family before he went to England.
=Before Tony went to England, he had a big dinner with his family.
在Tony去英国之前，他和他的家人吃了顿大餐。
Before和After当介词用法
Before/After后面接名词
He studies very hard before the test this time.
这次考试之前，他非常认真念书。
He bought many snacks before the field trip.
远足前，他买了很多零嘴。
When/Before/After后面接动名词
Before和After所引导从句，如果主语与主句相同时，去除从句的主语并将动词改为动名词。
After she ate dinner, she watched TV.
= After eating dinner, she watched TV.
吃完晚餐后，她看电视。
After she played the violin, she played basketball.
= After playing the violin, she played basketball.
弹完小提琴后，她打篮球。
Before she took the tests, she studied hard.
= Before taking the tests, she studied hard.
参加考试前，她用功念书。
Before you cook the vegetables, you must wash them.
= Before cooking the vegetables, you must wash them.
在烹煮蔬菜前，你必须先洗一洗。
When I watch TV, I usually have some popcorn.
= When watching TV, I usually have some popcorn.
当看电视时，我常常吃爆米花。
When I do the sports, I like to wear sneakers.
= When doing the sports, I like to wear sneakers.
当运动时，我喜欢穿运动鞋。
编辑推荐：
