all,back,we,are,school,at

(All the students )are back at school.对括号里提问. （ ）are back at are waiting we for all at you the gate school We ( ) school today ,Miss Gao.A、are all at B、all are at C、ar All the students are back at school.句中at能否换成to?为什么? We ****all at school yesterday. We----all at school yesterday. All the students are back at school on the first day of the are all the students back at school?is there a new building? we _____ going to meet at the school gate.a.are all b.all ar we are all ____(介词）school today.No one goes outand stays at Our children are all at school We are all back in home after school.这句话为什么要把in home 改成 home