Modal Verbs and Their Functions

What is the difference between must and have to?

When do we use must?

What does mustn't express?

What is the function of should?

What does had better express?

What is the correct usage of must in a sentence?

• I must remember to take my key.

• I must study to improve my grades.

• I have to wear my seatbelt in the car.

• He has had to change his diet before the marathon.

What is the correct usage of should in a sentence?

• He should stay home if he is sick.

• He shouldn't come to school.

• When you go to the city, you should get a metro pass.

• Should I go left or right?

What is the correct usage of ought to in a sentence?

• You ought to dress warm when you go to the mountains.

• When you visit a new country, you ought to try the street food.

What does had better express in a sentence?