I don't know when to leave

I don't know when to leave I don't know when leave 还是I don't know when to leaf I don't know when to leave为什么when后面要加to. i don't know when i should leave 同意句 I don't know when we should leave for Nanjing. 英语翻译I don't know when( )for Shanghai.(leave) I don't care when you leave because you don't know cherish m I don't know when we shall leave for Moon Bay.(改为简单句)为什么用to? I don't know when we will leave the city.(同义句） I don't know（ 初二英语题目,告急I don't know when we'll leave hereI don't know ____ when () Mr White __(leave) home?sorry I don't know I __(not I am unhappy,i don't know how to do?i want to leave here.