Welcome to the unit
1. listen to a headmaster talking about...
2. know of ; know about; know from ( 区分= tell from)
eg: 1) 我不认识他,但是我知道他。 2)他们想了解美国英语和英国英语的区别。 3) 我们应该分清敌友。
I don’t know him but I know of him.
They want to know about the differences between American English and British English.
We should know a friend from an enemy.
talk of / talk about; hear of / hear about/ hear from