before doing sth 行吗？
我看见有一个就是说 before having to make a turn。能介绍一下为什么这样用么？before doing sth 做某事之前 （完全正确的用法）
before having to make a turn 在必须转弯之前
例句与用法
1. We must have a plan before doing any work.
做任何工作前，我们必须订好计划。
2. We all should warm up before doing some exercises.
开始做运动前，我们都应该热身。
3. He always consulted others before doing anything .
他做什么事情都先和别人商量。
4. Take your time to reflect before doing important things.
在做重大的事情之前要从容不迫地思考一下。
5. But before doing so, I will briefly review recent events.
但在讲之前，我简短地回顾一下当前发生的情况。
6. Take enough time to reflect before doing important things.
在做重要事之前，先考虑一段时间。
before having to make a turn 在必须转弯之前
例句与用法
1. We must have a plan before doing any work.
做任何工作前，我们必须订好计划。
2. We all should warm up before doing some exercises.
开始做运动前，我们都应该热身。
3. He always consulted others before doing anything .
他做什么事情都先和别人商量。
4. Take your time to reflect before doing important things.
在做重大的事情之前要从容不迫地思考一下。
5. But before doing so, I will briefly review recent events.
但在讲之前，我简短地回顾一下当前发生的情况。
6. Take enough time to reflect before doing important things.
在做重要事之前，先考虑一段时间。
before doing homework
英语 定语从句的问题! Before doing homework,review important points mentioned in class_____ and points ______ you remain confused about.为什么不能选 and...what 选and.../important points mentioned in class and points (that) you remain confused about.
用and连接两个定语,前一个为后置定语,后一个为定语从句,其that可省略.
用and连接两个定语,前一个为后置定语,后一个为定语从句,其that可省略.
before+doing做什么成分
before 和after 作介词用时加doing，作连词用时引导时间状语从句，他们后面都不加do。
after/before+从句/doing例句
after
和before
引导时间状语从句时具体用法
before
所引导的时间状语从句
所表示的动作
发生在主句动作之后
如果强调主句的动作发生在前
主句谓语
要用过去完成时
before
引导的从句用一般过去时
如不强调动作的先后
主句和从句
均用一般过去时
如
she
worked
in
swww.souquanme.comhsnghai
before
she
came
here.
she
had
studied
english
for
six
years
before
she
went
to
college
另外注意
before
所引导的时间状语从句
常表示
。。。之后
才。。
如果主句
是一般将来时
从句用一般现在时
如
it
won't
be
long
before
we
meet.
again
不久我们就会再见面
after所引导的时间状语从句
所表示的动作
发生在主句动作之前
如果强调从句的动作发生在前
从句谓语
要用过去完成时
主句用一般过去时
如不强调动作的先后
主句和从句
均用一般过去时
如
after
he
did
his
homework,
he
went
to
bed
aXeHQjOlMKMfter
she
had
waited
for
him
for
an
hour
,she
started
for
home.
主句是
一般将来时
after
从句用
一般现在时或现在完成时
代替将来完成时
如
i
'll
write
to
you
after
i
finish
/
have
finished
my
work
和before
引导时间状语从句时具体用法
before
所引导的时间状语从句
所表示的动作
发生在主句动作之后
如果强调主句的动作发生在前
主句谓语
要用过去完成时
before
引导的从句用一般过去时
如不强调动作的先后
主句和从句
均用一般过去时
如
she
worked
in
swww.souquanme.comhsnghai
before
she
came
here.
she
had
studied
english
for
six
years
before
she
went
to
college
另外注意
before
所引导的时间状语从句
常表示
。。。之后
才。。
如果主句
是一般将来时
从句用一般现在时
如
it
won't
be
long
before
we
meet.
again
不久我们就会再见面
after所引导的时间状语从句
所表示的动作
发生在主句动作之前
如果强调从句的动作发生在前
从句谓语
要用过去完成时
主句用一般过去时
如不强调动作的先后
主句和从句
均用一般过去时
如
after
he
did
his
homework,
he
went
to
bed
aXeHQjOlMKMfter
she
had
waited
for
him
for
an
hour
,she
started
for
home.
主句是
一般将来时
after
从句用
一般现在时或现在完成时
代替将来完成时
如
i
'll
write
to
you
after
i
finish
/
have
finished
my
work
after/before+从句/doing例句
after 和before 引导时间状语从句时具体用法
before 所引导的时间状语从句 所表示的动作 发生在主句动作之后 如果强调主句的动作发生在//www.souquanme.com前 主句谓语 要用过去完成时 before 引导的从句用一般过去时 如不强调动作的先后 主句和从句 均用一般过去时
如 she worked in shsnghai before she came here.
she had studied english for six years before she went to college
另外注意 be//www.souquanme.comfore 所引导的时间状语从句 常表示 。。。之后 才。。
如果主句 是一般将来时 从句用一般现在时
如 it won't be long before we meet. again 不久我们就会再见面
after所引导的时间状语从句 所表示的动作 发生在主句动作之前 如果强调从句的动作发生在前 从句谓语 要用过去完成时 主句用一般过去时 如不强调动作的先后 主句和从句 均用一般过去时
如 after he did his homework, he went to bed
after she had waited for him for an hour ,she started for home.
主句是 一般将来时 after 从句用 一般现在时或现在完成时 代替将来完成时
如 i 'll write to y//www.souquanme.comou after i finish / have finished my work
before 所引导的时间状语从句 所表示的动作 发生在主句动作之后 如果强调主句的动作发生在//www.souquanme.com前 主句谓语 要用过去完成时 before 引导的从句用一般过去时 如不强调动作的先后 主句和从句 均用一般过去时
如 she worked in shsnghai before she came here.
she had studied english for six years before she went to college
另外注意 be//www.souquanme.comfore 所引导的时间状语从句 常表示 。。。之后 才。。
如果主句 是一般将来时 从句用一般现在时
如 it won't be long before we meet. again 不久我们就会再见面
after所引导的时间状语从句 所表示的动作 发生在主句动作之前 如果强调从句的动作发生在前 从句谓语 要用过去完成时 主句用一般过去时 如不强调动作的先后 主句和从句 均用一般过去时
如 after he did his homework, he went to bed
after she had waited for him for an hour ,she started for home.
主句是 一般将来时 after 从句用 一般现在时或现在完成时 代替将来完成时
如 i 'll write to y//www.souquanme.comou after i finish / have finished my work
