middle school 这是个词组 为什么school不加s又没说是单数

middle school 这是个词组 为什么school不加s又没说是单数 middle school 不是两个普通名词构成的专有名词.为什么前面不加the What’s your middle school? That's an () middle school middle school 的同义词组是? it’s time for school.这个句子中school前为什么不加冠词 名词所有格的省略?school policy对吗?school后为什么不加‘s? He's going to school..这里的 school为什么不加the. we wear school uniform at school.uniform为什么不加s? Junior high school 、Middle School ；Senior High School、High S middle school还是Middle School 为什么?什么情况下用? middle school