在学校或在上学用介词:in school, at school都可以,举例如下:
at school
a) in the school building 在学校
I can get some work done while the kids are at school.
b) British English 英国英语,求学 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 在学校
Sandra's not in school today.
b) American English 美国英语 attending a school or university rather than having a job:
Are your boys still in school?