题目内容
【题目】______ the air clean, we can take the metro to school. ( )
A.KeepB.To keepingC.KeepsD.To keep
【答案】D
【解析】
略
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题目内容
【题目】______ the air clean, we can take the metro to school. ( )
A.KeepB.To keepingC.KeepsD.To keep
【答案】D
【解析】
略