下课之后英语短语怎么说

"After class" is a common way to say "下课之后" in English. Here are a few other phrases you might use to describe the time after a class or lesson:

"When class is over"
"At the end of class"
"Once class is finished"

For example, you might say "I have to go to the library after class" to describe your plans for the time immediately following a class. You might also say "I always feel exhausted after class" to describe how you feel at the end of a lesson.