生态系统中物质循环的特点是[]A．周而复始的B．逐级递减的C．单向的D．双向的-八年级生物

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• 生物的尸体经过微生物分解后，可为绿色植物提供二氧化碳、水和无机盐______．-生物
• —Must we finish our homework before dinner?—No, you _____.[ ]A. mustn'tB. mustC. needn'tD.
• You _____ right.[ ]A. may beB. maybeC. can be-八年级英语
• 请根据如图所示生态系统，完成下列问题．（1）图中太阳能、水、二氧化碳、氮气都属于生态系统中的______．（2）图中所示蝗虫取食______，有______对足，善于______．（3）如果该生态系-
• It is raining hard outside, so we _____ stay in the classroom. [ ]A. must B. can C. have to D. might
• 根据你所学的生物学知识判断下列说法正确的是（）A．“有收无收在于水，收多收少在于肥”，这句话表明了植物的生长需要水和有机物B．既能生活在水中又能生活在陆地上的动物都属于两-生物
• You_____ smoke when you see the sign.[ ]A. mustB. shouldC. mustn'tD. needn't-八年级英语
• You play computer games for a long time. It’s bad for your eyes.A．shouldB．shouldn’tC．couldD．don’t ha
• 在如右图所示的食物网中，要使E的产量最高，把能量集中引向E的食物链应是（）A．A→B→C→EB．A→B→EC．A→DD．A→B→C-生物
• —Do we have to finish our homework this afternoon? —Yes, you _______. [ ]A. must B. can C. may D. ne
• 句型转换。根据所给提示，完成句型转换。每空一词，含缩略词。 1. He can play the guitar. (改为一般疑问句,并作否定回答)________ he play the guitar
• —I can't get to sleep at night.—You ____drink coffee at night.[ ]A. shoulds B. shouldn'tC.
• 关于生产者、消费者、分解者的叙述，错误的是（）A．能将有机物分解为无机物的生物都叫分解者B．消费者的身体细胞表面一般都没有细胞壁C．在光下能放出氧的生物一般都是生产者D．生-生物
• 在草原生态系统的一些生物部分和非生物部分中，有阳光，草，水和无机盐、牛，细菌等．请根据以上说明回答．（1）在这个生态系统中，生产者是______，消费者是______．二者之间存在-生物
• Multiple choice. （5分）1. He mustn’t ________ a car _________.A drives, dangerously B drive, dangerous
• -Mom, _____ I go and play for a moment?-OK. [ ]A. do B. willC. shallD. must-八年级英语
• —______ you hear me clearly from far away?—Sorry. I can't.Say it again, will you?[ ]A. May B. n
• —I can't find my watch. Where is it?—It _____ in your bag. [ ]A.canB.may C.maybeD. may be-八年级英语
• 句型转换。1. I can drive a car. (改为否定句)I ______ ______ a car. 2. She can draw well. (改为一般疑问句) ______ she
• 下列有关生态系统的描述，正确的是（）A．生态系统中的物质流动是单向的B．生态系统是由生产者、消费者和分解者组成的C．生态系统内的能量是通过食物链和食物网来传递的D．研究生态-生物
• That dictionary ______ belong to Gina．Tom’s name is on it． A．must B．can’t C．could-九年级英语
• He _____ the work today if he doesn't want to.[ ]A. need't finishB. had finishedC. can
• 下列生物中属于生产者的是（）A．青菜B．金鱼C．细菌D．蘑菇-生物
• —Must I finish writing the composition today? —Yes, you ____. [ ]A. must B. can C. need D. may -八年级英
• My mother can play computer games but my father _____ . [ ]A. isn't B. doesn't C. aren
• 太阳的能量最先进入生态系统的（）A．生产者体内B．草食动物体内C．肉食动物体内D．分解者体内-生物
• “一山不容二虎”这句谚语，用生态学的观点来解释应是（）A．虎的性情孤僻，不喜欢群居B．虎是营养级别很高的生物，可得到的能量少，个体数量也就少C．虎的性情凶残，把幼虎吃掉了D-生物
• —May I try on the jeans?—Of course you _____.[ ]A. shouldB. need C. can D. must-九年级英语
• I ____like to help kids with their schoolwork. [ ]A. could B. wouldC. shouldD. will-九年级英语
• —Where _______ you like to go? —I’d like to go to France. [ ]A. will B. do C. would D. did -九年级英语
• 如图所示为草原生态系统的食物网示意图，能量从蛇传递到鹰的效率约为（）A．10%～20%B．50%～60%C．80%～90%D．100%-生物
• 在一个朽木的空洞中，底部有积水常存，洞中生物有细菌、原生动物、苔藓、蚊子和蜘蛛．这一朽木洞可构成一个（）A．食物链B．食物网C．生物圈D．生态系统-生物
• 句型转换。1. My mother can play table tennis.(改为否定句) My mother ______ ______ table tennis. 2. Lingling�
• Who is it be. it _____ be susan.it _____be susan.he is in beijing now.[ ]A.may . can't B.can.ca
• Sixteen-year-olds to watch this kind of movie because it's too scary.[ ]A. should allow B. shou
• 如图表示某生态系统中食物网简图．图中甲--庚代表各种不同生物．请据图分析回答：（1）此生态系统中作为生产者的是______，消费者是______．（2）若此生态系统受重金属污染，那么在体-生物
• 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 walletbe Tom's or B
• 有关“生产者是生态系统的主要成分”的理解，正确的是（）①生产者能将无机物合成有机物，属于自养型生物②生产者的细胞呼吸将有机物分解成无机物，实现了物质的循环③绿色植物的蒸-生物
• She ________ hum pieces of music at the age of four. She is a talented singer. [ ]A. can B. could C.
• — ______ I have a ticket, please? — Sorry, sir. All the tickets were sold out ten minutes ago. [ ]A.
• —Must I park my car behind the building?—No, you _ . You _ park it here.[ ]A. mustn't; may B. m
• 用must, mustn't, can, can't填空。1. Don't open your present now! In China you _____ wait
• The backpackbe Linda's. It be Grace's. I saw it at herhome before.[ ]A. mustn't, must
• 在自然界中，树木不断掉落树叶，动物不断地死亡，却不会出现树叶和动物尸体堆积如山的状况，这主要是因为（）A．被雨水冲走B．大雪掩埋C．树叶被风吹跑，动物尸体被秃鹫取食D．分解-生物
• 关于生态系统的能量流动，下列叙述中不正确的是（）A．稳定的生态系统必须不断地从外界获取能量B．生态系统中的能量最终来自于太阳能C．生态系统的能量流动可以循环进行，提高能量-生物
• 某一湖泊生态系统的食物链为藻类→虾→小鱼→大鱼，此食物链中的四类生物按顺序以甲、乙、丙、丁为代号建立能量金字塔（如右图）．今有10只人工饲养的鳄鱼逃逸栖居进入该湖泊，则该-生物
• My pen pal told me that he come to watch the Olympic Games in August 2008. [ ]A．will B．would C．can D
• —_____ you read books? —Yes, I _____.[ ]A. Can, do B. Do, can C. Can, can D. Can, read-七年级英语
• —Is the man over there Mr White?—No, it_____ be him. I saw him in the office a minute ago.[ ]A. may
• It's cold outside . We _____ stay in the classroom[ ]A.mustB.can C.havetoC.might-八年级英语