a drop quiz

例句：

1. 1. I need to take a drop quiz before the exam.
   考试前我需要做一次小测验。
2. 2. He gave me a drop quiz about his new book.
   他给我做了关于他的新书的小测验。
3. 3. The teacher asked us to take a drop quiz on the material covered in class.
   老师要求我们做一次课堂内容的小测验。