4. shall and should

The harvest festival begins on Sunday. We shall be there with our friends before that.

When going by plane, you should arrive at the airport at least one hour early.

It's nearly time for class to start. The teacher should be here soon.

5. must and can't

When you eat fish, you must be careful with bones.

Wang Feng has won the English competition three times. He must be very smart.

A man landed on Mars? You must be joking. That can't be true.

Step Ⅱ Underline the sentences containing modal verbs in the reading passage and label each sentence with the function of the modal verbs used-intention, duty, permission, possibility, guessing and ability. (page13, Exercise 1)

1. Underline the sentences containing modal verbs in the reading passage and use the function words below to explain the meaning of modal verbs.

Intention Duty Permission Possibility Guessing Ability Suggested answers:

Then by lunchtime they would all be sold. (possibility)

By now his restaurant ought to be full of people. (possibility)

What could have happened? (possibility)

Something terrible must have happened if... (guessing)

I'll help you lose weight... (intention)

He could not believe his eyes. (ability)

Perhaps he should go to the library and find out. (duty)

He could not have Yong Hui getting away with telling people lies! (intention)

He had better do some research. (duty)

Even though her customers might get thin after eating Yong Hui's food. (possibility)

They would become tired very quickly. (possibility)

...could win his customer back. (ability)

Step Ⅲ Explain the meaning and basic usage of the following modal verbs: