請假用英語怎么表達(dá)

　　I have to ask for leave tomorrow morning.

　　我明天上午得請假了。

　　If I were to ask for leave, would he agree?

　　如果我請假，他會答應(yīng)嗎？

　　He went to the headmaster to ask for leave.

　　他為請假找了校長。