Question

You should do what your teacher tells you to do (use modal auxillary showing obligation)​

Answer 1

Answer:

You have to do what your teacher tells you to do.

The modal auxiliary is the form of an auxiliary verb. It expresses necessity, possibility, obligation, and probability. To express obligation 'have to' and 'must' is used. 'Have to' expresses the obligation which comes from others.

Explanation:

Answer 2

Answer:

You must do what your teacher tells you to do.

Explanation:

must- It is used as an obligation word.