去 + 上学 / Subject + 上学
The verb phrase 上学 (shàngxué) means "to go to school" or "to attend school" and refers to the act of going to or being enrolled in school. It combines 上 (to go up/attend) with 学 (study/school). It can be used with 去 for emphasis, as in 去上学 (go to school), and is common in everyday conversation.
弟弟明天第一天上学,他很兴奋。
Dìdi míngtiān dì yī tiān shàngxué, tā hěn xīngfèn.
My younger brother starts school tomorrow for the first time, and he's very excited.
小时候我每天走路去上学。
Xiǎo shíhòu wǒ měi tiān zǒulù qù shàngxué.
When I was little, I walked to school every day.
孩子们该上学了,快出门吧。
Háizimen gāi shàngxué le, kuài chūmén ba.
It's time for the kids to go to school — hurry up and head out.