在学校是at school.
1、at school表示“在学校、在上学”相对于在家里或在校外。如：
My son is at school now. He is not at home or somewhere else.
我儿子现在在学校，他不在家，也不在别的地方。
2、in school表示“在求学、在上学”相对于有工作。如：
My daughter still in school She doesn’t work.。
我女儿还在上学，她不在工作。
扩展资料：
in与at的比较：
用于地方时，at指较小的地方，如指城镇时，in指较大的地方，用于省、国家、大陆前。国际大都市前用at 和in都有，但在London前通常用in。在指说话人的住处时要用in，且一般in表示实在的存在，而at却不是。
说到某大城市的某大销旦握建筑物，往往在大城市名称的前面用at，如the Pantheon at Rome。说到商店、机关、学校等，假使看作一个地点（point)用at。亏庆
假使看迟侍作一个场所(place)用in，the barber's (理发店），Green's (Green所开的店）等前面只用at，不用in。说到门牌用at，如live at 1184 Zhongshan Road，路名前面该用in，而说“在……路口”用at。
. at school
表示“在学校、老磨猜在上学”相对于在家游滑里或在校外。如：
My son is at school now. He is not at home or somewhere else.
我儿子现在在学校，他不在家侍型，也不在别的地方。
When my brother was at school, he studied very hard.
在学校时，我兄弟学习很用功。
. in school
“在求学、在上学”相对于有工作。如：
My daughter still in school She doesn’t work.。
我女儿还在上学，她不在工作。
at school 是“在上学”，in school或者in the school的意思是“在学校”
都可以
at school
a) in the school building:
I can get some work done while the kids are at school.
b) British English attending a school, rather than being at college or university or having a job:
We've got two children at school, and one at university.
in school
a) in the school building:
Sandra's not in school today.
b) American English attending a school or university rather than having a job:
Are your boys still in school?
当然是at school