让步根本未能平息学生的愤怒。
The concessions did little to placate the students.
不到20个学生考试全部及格。
Fewer than 20 students passed all the exams.
学生须在8:30以前到校。
Students are required to be in school by 8.30.
学生可以免做16–18题。
If you are a student, you can omit questions 16–18.