would do和used to do表过去习惯时到底有什么差别？

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would do和used to do虽然都可以表过去习惯，而且有的时候可以相互替换，但它们却存在以下几点区别：

（一）

would do一般用来表示过去反复进行的动作，而used to do则既可以表过去反复发生的动作，也可以表示状态。如：

1）would do

Every Saturday I would go on a long bike ride.

My dad would read me amazing stories every night at bedtime.

2）used to do

We used to live in New York when I was a kid.

She used to smoke， but she gave up a few years ago.

（二）

would do一般没有否定表达，而used to do则肯定和否定都可以。如：

There didn't use to be a supermarket there. When did it open?

Did you use to have a garden?

（三）

would do所在的句子一般会先给出过去时间背景，然后才能用would do，但used to do则无需如此。如：

1）would do

When I was a child, I would watch cartoons with my dad in the mornings.

When I was a student, I would read books in the library every Friday.

2）used to do

I used to watch cartoons with my dad in the mornings, when I was a child.

I used to read books in the library every Friday, when I was a student.

（四）

would do中的do一般不能是像be、understand、feel、love这样的静态动词。如：

错误：When I was a kid, I would feel happier.

正确：When I was a kid, I used to feel happier.

再比如：

错误：I would have long hair.

正确：I used to have long hair.

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