情态动词能和be able to连用吗

一、 先讲一下be able to和can的用法区别：

基本释义：当它们表示能力的时候，是一样的。如：

He can speak two foreign languages.

He is able to speak two foreign languages.

区别：

1. can只有两种时态, 即can 和could, 而be able to 有多种时态, 如was/were able to, will/shall be able to, have/has been able to等:

I’ll be able to drive the car in a week.

Through his diligent work, the deaf-mute has been able to read and write in a sign language.

Parents will be able to discuss their child's progress with their teacher

家长将可以和老师交流谈论子女的进步情况。

Without them you will not be able to fulfil the tasks you have before you

没有他们你将无法完成面临的任务。

We shall be able to tell whether you've kept your side of the bargain.

我方应能知道你方是否遵守了协议。

2．表示过去通过努力终于做成了某事要用be able to，而不能用can。如：

I was able to swim to the bank after the boat turned over.

can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can, could．be able to 则主要指具体做到了某件事的能力，其形式主要是靠be 发生变化，所以形式比can 多．可以说：I can swim. I am able to swim. 但是不能说：All the people could escape from the big fire in time. 只能说：All the people were able to escape from the fire in time.

3．can能表猜测，be able to不能。can的这种用法主要用于疑问句和否定句。

Somebody is knocking at the door. Who can it be?

It can’t be our teacher who is knocking at the door.

4．can 可以表 “允许”, 与may可以互换, 此时不能用be able to 代替。如： Can /

5. can 是情态动词，只能用作谓语成分，be able to是普通动词短语，既可以作谓语，也可以作非谓语。如：

How I long to be able to communicate with the foreigners in fluent English!

6. be able to 后边接动词不定式表示一种实际情况时，其否定形式不是be not able to，而是cannot。如：

Were you able to catch the first bus yesterday morning?

7. 一般说来, be able to 后边的动词不定式没有被动语态。如:

I’m sure he is able to correct his mistakes in grammar.

8. 在过去时中，could 表示“能够”，was / were able to 表示“得以做成”，即后者的动作完成了，前者只是一种可能性。（这个重要，五颗星）

He could leave Europe before the Second World War. 他在二战开始前能离开欧洲。（有没有离开，不知道）

He was able to leave Europe before the Second World War. 他在二战开始前得以离开欧洲。（成功离开）

二、be able to还可以和其他的情态动词连吗？答案是肯定的。如：

You have to be able to describe things in a form that the end user can understand.

你必须以终端用户可以理解的方式描述产品。

They may be able to help with childcare so that you can have a break

他们可以帮忙照料孩子，这样你就可以歇一歇了。

If only I could get some sleep, I would be able to cope.

要是能睡上一会儿，我就能应付了。

We may not be able to do it to the extent that we would like.

我们也许无法把这件事做到我们希望的程度。

He was both willing and able to subordinate all else to this aim.

为了这个目标他愿意并能够把其他一切都放在次要的位置。

They seemed able to work together very efficiently.

他们看来能很有效率地合作。

We may be able to design a course to suit your particular needs

我们或许可以专门设计一门课程以满足你的特殊需求。

He may be able to leave hospital early next week.

他下周初也许就可以出院了。

Science may be able to provide some explanations of paranormal phenomena.

科学也许能够解释某些超自然现象。

If you need to return to the UK quickly, British Consular officials may be able to arrange it.

如果你需要尽快返回英国，英国领事也许能安排此事。

Any knowledgeable wine merchant would be able to advise you.

任何一个懂行的葡萄酒商人都可以给你提出建议。

They should be able to find you the best package to suit your needs.

他们应该能提供满足你需要的最佳套餐。

If you need help at work, your Personnel Manager should be able to help.

如果你工作中需要帮助，人事经理应该能帮上忙。

Doctors should be able to decide who they can safely let out of hospital early.

医生应该有权决定谁可以安全地提早出院。

They should be able to comport themselves as they want.

他们应该能够自由地表现自我。

Any competent computer buff should be able to do it for you in a few minutes.

任何一个有点儿水平的电脑行家都能在几分钟内为你解决这个问题。

The older child should be able to prepare a simple meal

那个年纪稍大的孩子应当会做一顿简单的饭菜。

You should be able to find the odd moment for relaxation

你应该能抽空休息一下。

He should be able to keep his room tidy with the generous amount of storage space.

有那么宽绰的储物空间，他应该可以保持房间的整齐。

Individualists say that you should be able to wear what you want.

特立独行者认为人应该想穿什么就穿什么。

Boys at that age should be able to explore and go off on their own, go on bikerides, get into mischief

那个年龄的男孩应该可以自己出去闯，也可以骑车出游，还可以调皮捣蛋。

Wallcoverings and floors should be able to withstand steam and splashes

墙面材料和地板都应该能耐热汽且防水。

以上例子均摘自《柯林斯高阶英汉双解学习词典》