Could and Can

The Differences between Could and Can

1.       Modal Auxiliaries of Making Request

e.g

Ø Could you lend me your book, please?

This sentence is usually used for a polite request and formal request. It is used for making request to someone older.

Ø Can you lend me your dictionary?

This is used for informal request which is ordered to someone in the same age.

2.       Modal Auxiliaries of Offering Help

e.g

Ø Can I help you?

This expression is used for offering help to someone generally.

Ø Could I help you?

While this expression is used for offering help to someone which we know that they need help.

3.       Modal Auxiliaries of Showing Possibility

e.g

Ø Learning language can be difficult if we seldom practice

The sentence tells that the fact which will be occured in the future if we dont practice hard. But sometimes it will not happen.

Ø If you don’t hurry, you could be late

This sentence shows that the possibility of situation which can be occured.

4.       Modal Auxiliaries of Ability

e.g

Ø I could dance very well when I was in 12 years old.

It tells the ability in the past.

Ø I can play tennis very well

It tells the ability in the present

5.       Modal Auxiliaries of Permission

e.g

Ø Could I go home early today?

This sentence shows asking a permission for the action of someone.

Ø Can I borrow your jacket tomorrow?

While this sentence shows for asking a permission for the things.

6.       Modal Auxiliaries of Regret

To show a regret, we can only use a form Could+V3. This is caused something that was not expected to happen in the past, just like Conditional Sentence Type 3.

e.g

Ø I could have been a doctor if I had learned seriously.

This sentence show that someone has regreted to do something in the past.