Grammar : Use of Modals " Can"

Education English | Grammar : Use of Modals | The use of auxiliary modals "can" be used for:
1. Demonstrate the ability, for the present and future.
    He can speak English fluently.
    I can give it to you tomorrow.

2. Indicates permission.
    You can go to my office if you want to.

3. Indicates Possibility
    The animals can bite you if you get too close to it.
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Skill 18 : Base Form Verbs After Modals

Whenever you see modal such as will, would, shall, should, can, could, may, might, or must, you should be sure that the verb that follows it is in its base form.

You must telling her the truth.
The child may comes in now.

In the first example, telling should be the base form tell because it follows must. In the second example, comes should be the base form come because it follows may.

The following chart outlines the use of verb forms after modals.
Verb Forms After Modals : Modal + Base form of the verb