I am going home in about an hour.本句中为什么要用in 用at 或after

I am going home in about an hour.本句中为什么要用in 用at 或after After school ,I play football ______ an hour.A.at B.in C.for an at she home will be in hour I watch TV about half an hour 选for on at in 哪一个 I am leaving to Beijing in half an hour.翻译 I am at home=I am in吗如图,3 She look after David at home.请翻译成汉语,为什么after.为什么不用at,for,或in in an hour和after an hour用法分别是什么 I am in Year 7 at Walker School前面为什么用in而后面用at? in an hour /within an hour用什么时态 英语在线连词成句 an english books,bookstore,in the,I am,going to,buy i am going to talk about food in china