生态系统中能量流动的特点是（）A．循环往复，逐级递增B．单向流动，逐级递增C．循环往复，前后不变D．单向流动，逐级递减-生物

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• 根据如图生态系统中的生物，分析回答下列问题：（1）请在图上用箭头画出所有的食物链．（2）这个生态系统共有______条食物链，它们相互交错形成______，写出最长的一条食物链：____-生物
• 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
• —Could you please tell me the way to the station?—Sorry, I’m a stranger too. You ______ ask the poli
• —_____ he play table tennis?—No, he _____. [ ]A. Is; isn't B. Can; can't C. Can; isn'
• 在生态系统中，下列哪项是消费者（）A．蘑菇B．野兔C．阳光D．牧草-生物
• — I keep the book a little longer?—Yes, you can.[ ]A. MustB. NeedC. CanD. Should-九年级英语
• —_____I get home before 7 ? —No, you needn’t.[ ]A. Must B. Should C. Can D. Will-八年级英语
• I often see lights in that empty house. Do you think I ______ report it to the police? [ ]A. should
• 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
• 若人吃的牛肉来自以玉米为饲料的牛，人和牛分别扮演的角色是（）A．生产者消费者B．消费者生产者C．消费者分解者D．消费者消费者-生物
• —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
• 根据句意，从方框内选择合适的情态动词完成句子。must, may, can, could, might, can’t1. The brown wallet_____be Tom’s or Bill’s
• — This capTina's. I know she has a red cap. — No, it be Tina's. I am wearing her cap now.
• —How about singing songs with me?—I’m sorry I can’t. Ihelp my father with his work. [ ]A. have toB.
• 把下列生物与它在生态系统中所占的位置用线连接-生物
• - your brother play basketball, John? -No, he .[ ]A. Is; isn'tB. Can; canC. Can; can'tD. A
• "Must I come here before eight o'clock?" "No, you ______." [ ]A. can'
• 请按各小题的要求转换句型，保持句子原意，每个空格只准填一个单词。 1．We don't usually have to get there too early. (改为同义的) We get
• 生态系统都是由生物部分和非生物部分组成，消费者是指（）A．人类B．所有动物C．细菌、真菌D．所有动物和细菌、真菌-生物
• 要使某一生态系统长期存在，除了非生物部分外，必须具有（）A．消费者和生产者B．生产者和消费者C．生产者和分解者D．生产者和人-生物
• Jack _______ swim when he was five years old. [ ]A. canB. could C. may D. must-八年级英语
• 下列说法错误的是（）A．我们饮用牛奶所获得的能量最终来自于太阳B．如果在人的皮肤表皮细胞内成功植入叶绿体，则我们人也能向植物一样进行光合作用C．植物的蒸腾作用会受到各种物-生物
• 下列各项生物中，属于生产者的是（）A．水草和小麦B．鱼虾和海带C．蘑菇和青菜D．食草鱼类和玉米-生物
• —Must I finish the job this afternoon?—Yes, you _____, but you ______ finish it now.[ ]A. must; must
• The bike _____ be Adam's. Look! His bag is on it.[ ]A. canB. mustC. can'tD. mightn't-
• —Where is Jack, please? —He_____ be in the reading room. [ ]A. need B. shall C. must D. would -九年级英语
• Maybe he can _____ in our club.[ ]A. beB. isC. /-七年级英语
• You ______ go and ask Meimai.She _____ know the answer. [ ]A. must, canB. must, mayC. need, mayD. ca
• 生态系统的组成成分有（）A．生产者、分解者和非生物成分B．生产者、初级消费者、高级消费者、分解者C．消费者、分解者、病毒、非生物成分D．生产者、消费者、分解者、非生物成分-生物
• 生态系统的结构越复杂，能量流动和物质循环的途径就越______，其抵抗外力影响的能力就越______．-生物
• Where are my keys? I _____ find them. [ ]A. aren't B. can't C. am not D. don't-七年级英语
• 某草原生态系统中生活着多种生物，其中有以植物各器官为食的羊、鼠和昆虫；有吃羊的狼；有吃昆虫的鸟；有以鼠为食的蛇；还有以鼠、蛇和鸟为食的鹰．根据上述信息回答下列问题-生物
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• Look! The light in the room is still on. Mr. Liuat work.[ ]A. mustB. can't beC. must beD. have
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• 动物在生物圈中属于（）A．自养生物、生产者B．自养生物、消费者C．异养生物、生产者D．异养生物、消费者-生物
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• —Must I finish the work before five o'clock?—No, you_____.[ ]A. needn't B. mustn't C.