1--They have to clean the classroom after school.(对划线部分提问）
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提问:What do they have to do after school?
2 be,I,have,to,bed,by,in,o'clock,nine(连词成句)
I have to be in bed by nine o'clock.
3.--What are your school rules?
--Well,we___eat in the classroom
A.don't B.not C.can't D.can
选C,学校的规则是不能在教室吃东西