Unit 5, Activity 2a

Index Activity 2b

Grammar: Using Modal Verbs to Express Obligation, Permission and Prohibition


We use SHOULD to point out a good choice or option:

You should get your wife some flowers for Valentine’s Day.

We use MUST for a situation where you have no choice:

All visitors must sign in.

Although the two words seem similar, there are many situations where only one of them can be used:

Wrong: You should get a visa before you visit China.
Right: You must get a visa before you visit China.

Wrong: You must recycle that plastic.
Right: You should recycle that plastic.