His work is to keep all the classrooms clean on the second flood.

他的工作就是保持二层的所有教室的清洁。

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Students are required to keep their classrooms clean and tidy after school.

下课离校前须保持课室清洁。

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Students are required to keep their classrooms clean and tidy after school.

下课离校前须保持课室清洁。

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