单词归类：将下列各组属于同一类的单词找出并写在横线上，不属于该类的写在括号内。
1. 时间类: cancel weekday night screen century
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2. 植物类: flower panda tree cat bamboo
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3. 天体类: sun moon land Mars point
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4.材料类: plastic reuse cloth dustbin steel
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