Question

Students are supposed ________ hard at school.

A．studying

B．studied

C．to study

D．study

Answer 1

C

试题分析：考查短语be supposed to do sth 应该做某事，被期望做某事。句意：学生们应该在校努力学习。选C。
点评：be supposed to do sth 应该做某事，被期望做某事。本句式中to是不定式符号，不能接动名词或者名词，只能接动词原形。