l have to be back tomorrow.其中back是何词性是何意思?

l have to be back tomorrow.其中back是何词性是何意思? be back to do sth 中back 是什么词性? 返回是go back to还是get bake to二者有何区别 be back与be come back或be go back有何区别 Go back与go back to有何区别? Can you stay here longer?____But I have to be back tomorrow. can you stay here longer?,but i have to be back tomorrow A.I 回到学校的词组是back to school还是be back to school或be back at school l have a sore back 的意思 tomorrow I___ [be] going to be back home i have no idea __ she will be back tomorrow. be back的用法看到书上是you are to be back by 9 o'clock那you are back