共用题干
Ecosystem
tures expand within a given area.You can say that an ecosystem is the natural environment where biological
organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you
and mne.Yes,we are all members of an ecosystem!naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en-
courage co-habitation（共居）between living and non-living things in a monitored environment,such as a
zoo or garden.they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to
help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to
animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest
of us to function,and this happens in a never-ending cycle until the living creatures die and break up back
in the earth.In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living
things within our environment like our air and water so we can continue living as a population.Since plants,
animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,
and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis-
placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone.
Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals. In an ecosystem,plants,animals and humans live together in________.
organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you
and mne.Yes,we are all members of an ecosystem!
courage co-habitation（共居）between living and non-living things in a monitored environment,such as a
zoo or garden.
help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to
animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest
of us to function,and this happens in a never-ending cycle until the living creatures die and break up back
in the earth.
things within our environment like our air and water so we can continue living as a population.Since plants,
animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.
and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis-
placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone.
Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals. In an ecosystem,plants,animals and humans live together in________.
参考答案: C
参考解析: 由第二段的“There are different kinds of ecosystems depending on the type of surface or en- vironment.Most are naturally made...Some are man-made...”可知该段主要介绍了不同种类的生 态系统。故选B。
第三段讲到，根植于土壤中的植物利用空气和阳光促进自身生长，又成为动物和微生物的食物来源，而动物死后则又分解到土壤中二所以此段讲的是生态系统的工作原理。
第四段的主要内容是，生态系统是一切生物生存的基础，我们需要从中获取各种生存所 必需的物质。
此段主要讲要维护生态系统，我们需要做些什么，从“To preserve our ecosystems, we should stop using too much energy...""Humans should not disturb the natural habitat..."等表述可 以看出来。
由第一段第二句话“An ecosystem is where living creatures expand within a given area.”可 看出答案。
山第三段第三句话“When they grow, the plants and their fruits or flowers eventually be- come a source of food to animals…”可知答案。
由第四段末尾“…we all play a role in maintaining the ecosystem.”可知答案。effective在 此意为“起作用的”。
由最后一段第一句话“To preserve our ecosystems, we should stop using too much energy, which happens when we consume more than our share of resources.”可知答案。第4部分：阅读理解第一篇 文章主要讲的是公共上地在美国能源生产方面的重大作用，分别从产量、税收、未开发的传 统能源、替代能源占全国的份额以及能源开发需求等方面进行了介绍。
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