在一个稳定的池塘生态系统中，一种突发的污染使所有的植物死亡，在科研测量的变化中，首先降低浓度的是（）A．二氧化碳B．无机盐C．氧气D．一氧化碳-生物

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• 用can或can't加下面一个动词填空。 speak, see, hear, play, color, ask, drive, fly, spell, go1.I'm sorry
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• — I keep the book a little longer?—Yes, you can.[ ]A. MustB. NeedC. CanD. Should-九年级英语
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• 句型转换。1. It's necessary to study hard in the school.(同义句)______ ______study hard in the school.
• 下列叙述正确的是（）A．在一个生态系统中，生产者、消费者、分解者是紧密联系、缺一不可B．维持生态平衡，就是维持生态系统内部各种生物的数量稳定不变C．人类所需的资源中，土地-生物
• _____ you ride _____ horse? [ ]A. Are; the B. Can; a C. Are; a D. Can; the-七年级英语
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• —Bill, is the pink umbrella Anna’s?—No, itbe hers. Hers is purple. [ ]A. canB. may not C. wouldD. ca
• 如图示草原生态系统，请分析回答：（1）此生态系统中的生产者是______，分解者是______、______．（2）生产者与消费者之间的关系主要是______的关系它们之间相互交叉形成了______，
• 从“狼吃羊，羊吃草”可以看出，狼体内的有机物最终来源于（）A．草B．水C．羊D．阳光-生物
• You_____ be so hurry as the time is not so late.[ ]A. mustn’t B. mustC. can notD. will not-八年级英语
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