summer school
noun [ C ] uk/ˈsʌm.ə ˌskuːl/ us/ˈsʌm.ɚ ˌskuːl/
暑期班，暑假课程
an educational course that happens during the summer holidays
They organize an annual summer school for young musicians. 他们为青年乐手组织一年一度的暑期课程。
US（为补足因缺课、不及格失去的学分或为加快学生学习进度以尽早拿到学位或毕业而开办的）暑期学校，暑期补习班
one or more classes taken during the summer that replace classes that were missed or failed, or make it possible for students to move more quickly towards a degree or graduation
The students had improved enough after summer school to be promoted to 4th grade. 这些学生在暑期补习班提高了很多，有资格升入四年级了。