1、both 指的是两者全都 all指的是三者以上 both of +us/them/you 我们、他们、你们俩 both A and B A和B俩 both 和all 用于be动词之后，实义动词之前，强调俩都，全都的概念 My father and mother are (both) teachers. They (both) work at the same school. be away from是leave 的延续性动词。

2、leave 是瞬间动词 用在表示延续性时间for +一段时间中，要把leave 变成be away 离开某地就代表不在某地了 leave sw 要表示离开某地多久就要变be away from sw +for +一段时间 She has been away from Beijing for 2 years.她离开北京两年了、= She left Beijing 2 years ago. 她两年前离开的北京。