小华同学说：“爷爷讲在他小时候，村边的小河里有许多鱼、虾，稻田中有不少黄鳝和泥鳅。现在河里和稻田中几乎没有鱼、虾了。”这是什么原因呢？（1）请对上述情况做出假设：_______-八年级生物

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• —I still have a toothache. —Oh, sorry, the medicine didn't work, so you ________try another kin
• 研究生态系统的能量流动，可帮助人们合理地调整生态系统中能量流动的关系，使能量_________地流向对人类最有益的部分。-八年级生物
• I_____play the guitar.It's too difficult. [ ]A. canB. can't C. doesn't-七年级英语
• —You see, a man is cutting a tree on the moon. —It _________ be true. The teacher says there is no a
• 根据句意从方框中选用合适的词组，并用其适当形式填空 fix up take after hand out clean up call up 1.The teacher __________ all t
• That man _______ our head teacher. Our head teacher has gone to town.[ ]A. can't beB. mustn
• 改成同义句。1. Kate can't work out the math problem, I think. I ______think Kate ______work out the m
• 下图是珠江三角洲的农民充分利用自然条件，建立的该地特有的蔗基鱼塘和桑基鱼塘示意图。请据图回答：（1）这种人工生态系统最基本的生物因素是___________。要使它长期稳定发展-八年级生物
• This building is too old and dangerous.It should ___dowm[ ]A. to pullB. pullC. is pulled D. be pulle
• —I was told to be here before 6:00 p.m.— Oh, you . I felt sorry for you that we've changed the
• 生态农业的最大优点是[]A．物质循环不再生B．能量的多级化利用C．生物相互依存D．不用人类参与-八年级生物
• You ______ jump onto a bus while it is still moving. It is too dangerous. [ ]A. can B. must C. can&#
• —Must we wear our school uniform this afternoon?—No, you _____. All of us will go on an outing.[ ] A
• 句型转换1. I like playing football. (否定句)I ______________ playing football.2. I wanted soup for supper.
• You ________ your homework now.You can do it tomorrow.[ ]A.needn't to doB. don't need doC.
• My mother is ill. I __________ stay at home to take care of her.[ ]A. canB. mayC. shouldD. maybe-八年级
• 一般地说，在输入到一个营养级的能量中，只有的能量能流入下一个营养级。-八年级生物
• 在生态系统内，与碳循环始终结合在一起进行的是[]A．氮循环B．水循环C．能量流动D．能量循环-八年级生物
• —Would you like to see Beijing Opera with me tonight?—I'd like to, but I'm afraid I ______
• The little boy _____ write, but the girl can. [ ]A. may not B. must not C. can't D. needn'
• —Dad, must I practise the piano today?—No, you _. You may do it tomorrow.[ ]A. needn’tB. mustn’tC. s
• 从物质循环的观点看，生物体内碳元素的最终来源是[]A．食物所含有机物中的碳B．非生物界中的碳酸盐C．大气中的二氧化碳D．生态系统中的生产者-八年级生物
• Must I take the medicine every day?-No, you __________.[ ]A. mustB. mustn'tC. needn'tD. ca
• 由于生物自身的消耗，以及植物的残枝落叶和动物的骨骼、皮毛等难以被_____利用，造成了能量在沿食物链流动过程中是逐级的。-八年级生物
• There is no bus at this time every night. You ____ walk home.[ ]A. mustB. have toC. canD. need-八年级英语
• You _______ go to bed early, or you can't get up on time.[ ]A. canB. shouldC. mayD. must-八年级英语
• 生态系统中的能量流动伴随着__________。-八年级生物
• He ______more fruit and vegetables instead of meat.[ ]A. need to eat B. needs to eatC. need eating D
• -Must we hand in the money for the tickets now?-No, you __________.[ ]A. mustn'tB. can'tC.
• 我国北方地区，二氧化碳含量相对较高的季节是[]A．春季B．夏季C．秋季D．冬季-八年级生物
• —Must I finish that work today?—No, you _____. You may finish it in three days.[ ]A. mustn’tB. needn
• 生态系统中能量的、和的过程，称为生态系统的能量流动。-八年级生物
• If you want to join us, you __________ help kids with their schoolwork.[ ]A. wouldB. have toC. could
• —I'd like to do somle volunteer work,but I'm not sure what I should do. —You ______ give o
• —I answer this question in English? —No, you .Youanswer it in Chinese.[ ]A. May, needn't, can B
• 碳循环的主要形式是[]A．碳元素B．二氧化碳C．碳酸盐D．有机盐-八年级生物
• “Can you sing the song in English?”“No , I _________”[ ]A. may not B. mustn’t C. needn’t D. can’t-九年
• 生态系统中能量的源头是。生产者通过光合作用把太阳能固定在它们制造的______中，太阳能就转变为，输入了生态系统的第一营养级。随后将能量从第一营养级传递到第二营养级。当-八年级生物
• 动词填空。1. What a beautiful picture! Can it ________ (put) up at Christmas? 2. —Where's my pen? —I
• What _____ you like?[ ]A. canB. areC. mustD. would-七年级英语
• Tony hasn’t come to school yet. He __________ be ill or has something wrong.[ ]A. mayB. willC. needD
• The room is big enough .It _______hold 1000 people.[ ]A.mayB. mustC. can D. have to -九年级英语
• —Where is Tom? —He didn't come to school today.I think hebe ill. [ ]A. has to B. shouldC. mayD.
• 碳循环中，能使二氧化碳进入生物体内，又能将其释放到大气中的是[]A．生产者B．消费者C．分解者D．以上都可以-八年级生物
• 森林生态系统往往降雨较多，其主要原因是[]A．蒸腾作用使大气湿度增加B．光合作用旺盛，利用水分多C．呼吸作用较弱，产生水分少D．蒸腾作用使大气湿度减少-八年级生物
• 试根据生物圈中循环的图解，回答问题。（1）图中A、B分别代表的生物种类是：A，B。（2）图中a表示作用，b表示作用，c表示作用，d表示过程。-七年级生物
• I __work out the maths problem.Lily____know the answer.Let's ask her for help.[ ]A.can'tmu
• 能量流动和物质循环都是通过生物之间的________过程实现的。-八年级生物
• 如图表示生态系统中物质循环的过程，请据图回答问题：（1）图中①、②代表的生物分别是：_______和________。（2）图中③～⑥表示某生理过程，其中③⑤分别是__________、_______
• 由于“赤潮”的影响，一条4千克重的草食性海洋鱼死亡，食物利用率按20%计算，该杂食鱼从出生到死亡，共需海洋植物千克。-七年级生物