What are modal verbs

What are Modal Verbs?
Modal verbs are special verbs which behave very differently from normal verbs. Here are some important differences:
1. Modal verbs do not take "-s" in the third person.
Examples:
He can speak Chinese.
She should be here by 9:00.
2. You use "not" to make modal verbs negative, even in Simple Present and Simple Past.
Examples:
He should not be late.
They might not come to the party.
3. Many modal verbs cannot be used in the past tenses or the future tenses.
Examples:
He will can go with us. Not Correct
She musted study very hard. Not Correct

Common Modal Verbs Can
Could
May
Might
Must Ought to
Shall
Should
Will
Would
For the purposes of this tutorial, we have included some expressions which are not modal verbs including had better, have to, and have got to. These expressions are closely related to modals in meaning and are often interchanged with them.

Can
"Can" is one of the most commonly used modal verbs in English. It can be used to express ability or opportunity, to request or offer permission, and to show possibility or impossibility.
Examples:
I can ride a horse. ability
We can stay with my brother when we are in Paris. opportunity
She cannot stay out after 10 PM. permission
Can you hand me the stapler? request
Any child can grow up to be president. possibility
Using "Can" in Present, Past, and Future
Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how "can" behaves in different contexts.

Modal Use Positive Forms
1. = Present 2. = Past 3. = Future Negative Forms
1. = Present 2. = Past 3. = Future You can also use: can general ability 1. I can speak Chinese.
2. SHIFT TO "COULD"
I could speak Chinese when I was a kid.
3. SHIFT TO "BE ABLE TO"
I will be able to speak Chinese by the time I finish my course. 1. I can't speak Swahili.
2. SHIFT TO "COULD"
I couldn't speak Swahili.
3.