1、【 精品教育资源文库 】 Unit 4 Global warming . 阅读理解 A They may be tiny, and live for just three months, but ants could be the key to solving climate change. Rough harvester ants have been found to “weather” minerals in sand to produce calcium carbonate, also known as limestone(石灰岩 ) When the ants make this l
2、imestone, the process traps carbon dioxide in the rock, ultimately removing it from the atmosphere. It is uncertain how the minerals are changed, however, and theories vary a lot from ants licking the sand to excreting (排泄 ) the substance. Professor Dorn buried sand at six sites in the Catalina Moun
3、tains in Arizona, and Polo Duro Canyon in Texas, 25 years ago. Every five years, he measured the minerals in the sand, and discovered the ants broke down minerals up to 300 times faster than sand left undisturbed. Professor Dorn believes the ants collect calcium and magnesium(镁 ) and use these eleme
4、nts to make the limestone. This may occur when ants lick sand grains to stick them to the walls of their nests. Alternatively, the limestone could be created from bacteria in the insects gut before it is excreted. This process is similar to whats known as carbon sequestration(隔离 ) Natural carbon seq
5、uestration is the process on Earth that manages the carbon dioxide expelled by animals and humans. Trees and the oceans help trap this carbon dioxide. Another method is geological sequestration where the carbon dioxide is pumped into underground chamber, or into areas full of calcium and magnesium.
6、Carbon dioxide reacts with these elements to form limestone. It is this latter method that Dorn believes the ants perform naturally. But Professor Dorn claims it is still unknown how much atmospheric carbon is removed by the ants. 语篇导读 本文为说明文。多恩教授认为，蚂蚁也许是应对气候变化的关键因素。他通过实验证明蚂蚁能够吸收空气中的二氧化碳，但是具体能吸收多少至今
7、尚未确 定。 1 The fifth paragraph is mainly about _. A how ants break down limestone 【 精品教育资源文库 】 B how ants change minerals into limestone C how ants decorate their nests with sand D how ants use sand to kill bacteria 解析 B 主旨大意题。本段大意：多恩教授认为蚂蚁舔沙砾把它们粘在巢穴的墙上时，可能会收集钙和镁制造石灰岩 。或者，石灰岩可以从蚂蚁的肠道细菌中产生，再排泄出来。这都是关于
8、蚂蚁如何制造或产生石灰岩的，故选 B 项。 2 What is the possible meaning of the underlined word “expelled” ？ A Sent out. B Taken in. C Broken up. D Given away. 解析 A 词义猜测题。本句句意：地球上自然碳汇是处理动物和人类 expelled 的二氧化碳的过程。根据常识可知，动物和人类排放二氧化碳。 send out 放出； take in 吸收；break up 打碎，结束； give away 泄露 (消息、秘密等 )，故选 A 项。 3 According to Dorn
9、, scientists still dont know _. A the effect of CO2 on ants survival B the method of ants removing CO2 C the amount of CO2 removed by ants D the time when ants absorb CO2 解析 C 细节理解题。 根据最后一段可知，多恩教授目前尚不清楚蚂蚁吸收了多少大气中的碳，故选 C 项。 4 The main idea of the passage is that _. A ants build their nests to keep CO
10、2 out B ants use limestone to absorb a great deal of CO2 C ants are pioneers in solving global warming D ants may remove CO2 from atmosphere 解析 D 主旨大意题。第一段说 .but ants could be the key to solving climate change，后面介绍了多恩教授的实验，最后多恩教授称目前尚不清楚蚂蚁吸收了多少大气中的碳。因此全文主要讲蚂蚁可能会吸收大气中的二氧化碳并介绍相关实验，故选 D 项。 B During a re
11、search experiment a marine(海洋 ) biologist placed a shark into a large holding tank and then released several small fish into the tank. 5._ The marine biologist then inserted a strong piece of clear fiberglass(纤维玻璃 ) into the tank, creating two separate parts. She then put the shark on one side of th
12、e fiberglass and a new set of small fish on the other. 【 精品教育资源文库 】 Again, the shark quickly attacked. This time, however, the shark hit the fiberglass divider and bounced off. 6._ Meanwhile, the small fish swam around unharmed in the second part. Eventually, about an hour into the experiment, the
13、shark gave up. This experiment was repeated several dozen times over the next few weeks. 7._ Eventually the shark got tired of hitting the fiberglass divider and simply stopped attacking altogether. The marine biologist then removed the fiberglass divider, but the shark didnt attack. 8._ So, they sw
14、am wherever they wished, free from harm. Like the shark in the story, many of us, after experiencing setbacks and failures, emotionally give up and stop trying. 9._ In other words, we continue to see a barrier in our heads, even when no “real” barrier exists between where we are and where we want to
15、 go. A At the same time, the shark tried again and again. B We believe that because we were unsuccessful in the past, we will always be unsuccessful. C The shark was trained to believe a barrier existed between it and the small fish. D It kept repeating this behavior every few minutes fruitlessly. E
16、 We should keep on trying even if we meet obstacles. F Each time, the shark got less aggressive and made fewer attempts to attack the small fish. G As you would expect, the shark quickly swam around the tank, attacked and ate the smaller fish. 语篇导读 本文为议论文。大鱼吃小鱼是自然法则，也是鲨鱼的生存法则。然而，当鲨鱼与小鱼之间多了一块透明纤维玻璃后，
17、鲨鱼又会做出怎样的举动呢？ 5 解析 G 顺承关系。上句讲到：在一项实验中，海洋生物学家将鲨鱼放入一个大型水槽，并在水槽 中放入了几条小鱼。承接上句，空处应讲到放进小鱼的后果，即 G 项：正如你所想的，鲨鱼迅速在水槽中游动，袭击并吃掉小鱼，故选 G 项。 6 解析 D 顺承关系。本段共分为三个部分，第一部分讲到鲨鱼像上次一样进攻小鱼但被纤维玻璃弹开，第三部分讲到结果是鲨鱼放弃了吃小鱼，因此中间的一部分是承上启下，讲述鲨鱼一遍遍尝试的过程，故 A、 D 两项符合题意，然而 A 项中的 at the same time 与下文中的 meanwhile 重复，故选 D 项。 【 精品教育资源文库
18、】 7 解析 F 递进关系。上句讲到这项实验在接下来的几个星期里重复了好几十次。下句交代 了实验结果：鲨鱼最终疲于撞击纤维玻璃挡板，因此停止了攻击行为。在此之前，实验中所显现的过程如 F 项：每一次实验，鲨鱼的攻击性越来越弱，袭击小鱼的尝试越来越少，这与最终的结果构成递进关系，故选 F 项。 8 解析 C 诠释关系。上句讲到：海洋生物学家取出了纤维玻璃挡板，但鲨鱼还是没有攻击 (小鱼 )。空处则对鲨鱼这一举动作出解释，即 C 项：鲨鱼已经被训练得去相信挡板依然存在于它和小鱼之间，故选 C 项。 9 解析 B 顺承关系。上句讲到，与故事中的鲨鱼一样，我们许多人在经历挫折和失败后，就总想放弃并且不
19、再尝试。 B 项 (因为 过去有失败的经历，因此我们就认为自己总是会失败 )，承接上文并与下文表达同义，故选 B 项。 . 完形填空 Jaguar(美洲虎 ) is an endangered animal. It is said that there are less than 20 in the world _1_， one of which is now living in the national zoo of Peru. In order to _2_ this jaguar, Peruvians _3_ a pitch of land in the zoo for it, wher
20、e there are flocks of animals for it to eat. Anyone who has visited the zoo praised it to be the “Heaven of Tiger”. However, no one has ever seen the jaguar hunt the animals. _4_ people could see is its lying in house eating and sleeping. Some people thought the jaguar felt too lonely so they rented
21、 a female tiger to _5_ it. Nonetheless, it did not make much _6_. The jaguar just sometimes went out of its house with its “girlfriend” and stayed in the sun for a while. “I t is _7_ for the jaguar to be lazy in this environment. Tiger is the king of forest but you simply put some small _8_ around i
22、t. That is why it shows no _9_ in going out. Why dont you put two wolves around it？ ” a visitor proposed. Others _10_ him and put five panthers(黑豹 ) into its _11_. Since then, the jaguar didnt go back to its house any more. It either stood on top of the hill roaring or _12_ from the hill strolling without sleeping all day, totally got back
