Unit 1 Festivals around the world
语法探究
Teaching aims: Grasp the usages of some modal verbs and use them freely
课前自学（ SB P5-6 Discovering useful structures）
语法知识精讲
★ can表示“能力；许可；可能性”。表示“可能性”时指的是理论上的可能性。不表示某 事实际发生的可能性或真实性。例如：
A computer can’t think for itself; it must be told what to do.
电脑不具备独立思考的能力。
I should have been there, but I could not find the time.
You can come any time you like.
Anybody can make mistakes.
★表达某事实际发生的可能性时用may, could或might等。
We may spend our summer holidays in Hangzhou this year.
