按要求改写句子。

1. Jenny can play the piano. (改为否定句)

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2. I sometimes walk to school. (同义句)

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3. This isn't a new dress. (复数)

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4. These are men. (改为单数句子)

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5. Here are many dresses. (改为单数句子)

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6. It's a square. It's a rectangle. (合并为选择疑问句)

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机舱舱底防油污系统一般由（）、吸口、油污水驳运泵、（）、（）、污油柜、（）、阀门、管路及油分浓度报警器等组成。