What's difference and usage: Could and must

[Bijo]

Hi Everyone,

What's main difference between these words: ""could "" and "" must"".which appropriate place put these modal verbs.

kindly support for these issues

Thanks

Bijo

[Alan]

Hi,

'Could' has the sense of either 'would be able to' or 'was able to' depending on the context:

When I was a child I could (was able to) swim like a fish.

Today I honestly don't think I could (would be able to) swim even one length of the pool.

'Must' is a verb suggesting necessity or compulsion and can often be replaced by 'have to'

I must (it is necessary for me to/I have to) leave now in order to catch my train.

Alan
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