In China students greet the teachers when classes begin.
A. are suppose to
B. are supposed to
C. suppose
D. supposed to
网友回答
A. are suppose to
(答案→)B. are supposed to
C. suppose
D. supposed to
解析：此句的含义是在中国，学生们在上课前应该欢迎老师。考查的结构是be supposed to do sth意思是应该做某事，因主语students是复数形式，系动词be应用are，故选B。