单选题 A major reason for conflict in the animal world is territory. The male animal (1) an area. The size of the area is sufficient to provide food for him， his (2) and their offspring. Migrating birds, for example, (3) up the best territory in the order of "first come, first (4) ." The late arrivals may acquire (5) territories, but less food is available, or they are too close to the (6) of the enemies of the species. (7) there is really insufficient food or the danger is very great, the animal will not (8) . In this way, the members of the species which are less fit will not have offspring.
When there is conflict (9) territory, animals will commonly use force, or a (10) of force, to decide which will stay and which will go. It is interesting to note, however, that animals seem to use (11) the minimum amount of force (12) to drive away the intruder. There is usually no killing. In the (13) of those animals which are capable of doing each other great harm, (14) is a system for the losing animal to show the winning animals that he (15) to submit. When he shows this, the (16) normally stops fighting. Animals (especially birds), which can easily escape from conflict, seem to have (17) obstacle against killing, and equally no mechanism (18) submission. The losing bird simply flies away. However, if two doves are. (19) in a cage, and they start fighting, they will continue to fight until one kills the other. We all think of the dove as a symbol of peace and, in its natural habitat, it is peaceful. But the "peace" mechanism does not (20) in a cage.

单选题 A. establishes B. builds C. founds D. erects

【正确答案】 A

【答案解析】本题测试词义搭配。establish意为“建立，确立”．指奠定基础，继续地存在下去；build意为“建造，建筑”，指通过组合材料或部分而形成；found意为“创办，创立”，指所建立的东西只是初步的，仍有待于进一步的发展和完善；erect意为“树立，树起”，指使固定于一个竖直的位置。所填之词的宾语是an area(一块地盘)，所以应选establish。

单选题 A. wife B. mate C. friend D. neighbor

单选题 A. split B. break C. cut D. divide

【正确答案】 D

【答案解析】本题测试词义搭配。所填之词应该与后面的up搭配。split up意为“把……分裂”，指使……裂开；break up意为“分解，打碎”；cut up意为“瓜分赃物，切碎”；divide up意为“分割”，指分成几部分。所填之词的宾语是territory，所以应选D。

单选题 A. use B. serve C. served D. used

单选题 A. larger B. better C. smaller D. worse

单选题 A. caves B. nests C. residences D. habitats

【正确答案】 D

【答案解析】本题测试词义辨析。cave和nest通常指鸟兽的隐蔽处、安乐窝，有一定的范围限制；residence一般指人的居住地；habitat意为“居留地，栖息地”，指某种生物或生态群体生存繁衍的地区或环境。the enemies of the species修饰所填之词，所以应选D。

单选题 A. But B. If C. Since D. Because

单选题 A. breed B. produce C. mate D. compete

【正确答案】 C

【答案解析】本题测试词义搭配。breed意为“抚养，抚育”，指养育，训练；produce意为“生产，结果实”；mate意为“配对，繁殖”，指为了繁殖而配对；compete意为“竞争”。根据后面的the members of the species which are less fit will not have offspring可知，应选C。

单选题 A. for B. over C. with D. by

单选题 A. practice B. proof C. show D. comparison

【正确答案】 C

【答案解析】本题测试词义搭配。practice意为“实践，实际”；proof意为“证明，证据”；show意为“展示，炫耀”；comparison意为“比较，对照”。根据前面的use force和后面的decide which will stay and which will go可知，应选C。

单选题 A. only B. mostly C. mainly D. chiefly

【正确答案】 A

【答案解析】本题测试逻辑搭配。only意为“仅仅，只”；mostly意为“主要地，大部分”；mainly意为“主要地，大体上”；chiefly意为“主要地，首要”。根据however可知，本句话表示转折，并且根据后面的the minimum amount of force可知，应选A。

单选题 A. compulsory B. essential C. necessary D. vital

【正确答案】 C

【答案解析】本题测试词义搭配。compulsory意为“强制的，必须做的”；essential意为“根本的，基本的”；necessary意为“必要的，必需的”，指达到某种目的而必须具备的；vital意为“极其重要的，生死攸关的”。所填之词修饰force，根据后面的drive away the intruder。可知，应选C。

单选题 A. way B. case C. event D. manner

单选题 A. this B. that C. it D. there

单选题 A. wishes B. considers C. thinks D. decides

【正确答案】 A

【答案解析】本题测试词义搭配。wish意为“希望，想要”，指表达愿望；consider意为“考虑，认为”；think意为“思考，认为”；decide意为“决定，决心”，指下定决心。根据前面的．for the losing animal to show the winning animals可知，应选wish。

单选题 A. killer B. loser C. victor D. successor

单选题 A. any B. some C. every D. no

单选题 A. in B. for C. with D. by

单选题 A. placed B. perched C. deposited D. stationed

【正确答案】 A

【答案解析】本题测试词义搭配。place意为“安放，放置”，指放到某一特定的位置或地方；perch意为“使坐落于，使处于”；deposit意为“存放，堆积”；station意为“驻扎，配置”。所填之词的主语是two doves，根据后面的in a cage可知，应选A。

单选题 A. appear B. continue C. apply D. function

【正确答案】 D

【答案解析】本题测试词义搭配。appear意为“出现，露面”；continue意为“继续，持续”；apply意为“应用，适用”；function意为“起作用，发挥作用”。句子的主语是mechanism，根据but可知，本句话与前面的句子it is peaceful意思转折，所以应选D。