"开学了" 用英语可以说 "school is starting" 或 "school has started"。这个表达的来源可能源于学校的开学日期，在这一天，学生们开始上课。

例句：

The new school year has started, and I'm excited to see my friends again. (新学年已经开始了，我很高兴再次见到我的朋友。)

I can't believe it's already time for school to start again. (我简直不敢相信开学时间又到了。)