英语六级阅读理解训练附详解：动物世界

　　into play; in the last resort the snake attacks. This pattern vanes with the circumstances;some stages may be omitted or combined unpredictably whilst all some notoriously irasciblespecies may dispense with all the preliminaries and attack almost at once. though seldom ornever without some provocation.

　　Amongst the factors that increase aggressiveness are hunger, the mating season and surprise,with the last mentioned the commonest; when hunting for food or for mate. activity and theaggressive instinct are both at their peak. Owing to their poor sense of hearing snakes arevery liable to be, quite literally, caught napping and a similar situation arises during theirperiods of temporary blindness just before sloughing (蜕皮)begins. By far the greatestnumber of snake-bit accidents result from the unwitting disturbance of resting snakes. and thishazard is much increased with species that are well disguised and whose natural instinct is totrust to this concealment as their principal defense. As well as differences in aggressivenessbetween individuals of the same species according to the circumstances and conditions, thereare also notable differences between species, even closely allied species; and the reports ofthose who have been attacked may understandably be lacking in objectivity. So it isimpossible to forecast. even in outline, how any encounter will develop.

　　The Hamadryad, for example, is usually credited with being amongst the most aggressive ofsnakes. and there are many accounts of unprovoked attacks, yet on one occasion fourteenmen and seven dogs passed and returned within two yards from a nest and no snake was seenalthough the female. which guards the nest, could not have been far away.

　　蛇的品种繁多。有各式各样的天敌，无疑，它们有数之不尽的防御方式和武器。但是，它们有一种共同的行为模式。[1]在遇到可疑的敌人时，它们的第一反应就是设法避开对方的监视;如果这个不成功的话，第二个方法就是逃到一个对方难以接近的安全之地，但是，如果无处可躲或者陷入包围，它们就会摆出各种恐吓的姿势，向对方发出警告;如果以上所有的方法都不奏效，蛇就会向敌人发起攻击。[2J这种模式会随着环境改变;它们不一定逐一完成以上四个步骤，也可能毫无预警地把某些步骤结合在一起;而所有那些臭名昭著的残暴的蛇种，可能一开始就对敌人发起攻击，而摒弃所有其他的步骤，但是它们这样做通常是因为受到了挑衅。

　　[3]增加蛇的攻击性的因素有：饥饿、交配季节，还有最常见的——受到惊吓;在觅食和寻找交配对象的时候，蛇的行为和攻击的本能都达到最高峰。因为蛇的听觉很差，所以，在它们打盹的时候，通常最容易被捕获，蛇在开始蜕皮的时候会暂时失明，同样这时蛇也最容易被捕获。到目前为止，在被蛇咬到的事件中，大多数是因为人们无意中打搅了正在休息的蛇，而碰上那些伪装性很强的蛇(它们主要的防卫措施就是本能上依靠伪装隐藏自己)，人们受到攻击的危险就更大了。[4]因为环境条件的差异，所以在同一品种的蛇中，每条蛇的攻击性不一样，除此之外，不同的蛇种，即使近亲品种，也有明显的差别;于是，那些曾被蛇攻击过的人，他们的报告很可能缺乏客观性，这也是可以理解的。[5]因此，每一次当人蛇遭遇时，事情将如何发展，都无法预测，甚至概括性的预测也是不可能的。

　　[5]例如，人们常常认为眼镜王蛇是最具攻击性的蛇，它通常无缘无故对人发起攻击;然而，有一次, 14个人带着七条狗在距离蛇窝两码的地方来回走过，却一直没有看到蛇的踪影，但是，看守蛇窝的雌蛇必然就在近处。

　　1.When a snake meets a potential enemy, itsprimary device is______________.

　　A) avoiding any observation

　　B) Finding a safe shelter

　　C) giving a warning threat

　　D) starting a quick attack

　　2.The underlined phrase "dispense with all the preliminaries" in Paragraph I mostprobably means________________.

　　A) the snakes combine all the previous three steps

　　B) the snakes give up all the previous three steps

　　C) che snakes follow all the previous steps one by one

　　D) the snakes reverse the order of all the previous steps

　　3.A snake is most aggressive when_______________.

　　A) it meets a possible enemy

　　B) it is caught when it is sleeping or sloughing

　　C) it is disturbed unknowingly

　　D) it seeks a partner in che mating season

　　4.It is difficult to predict what would happen when a snake meets a manbecause____________.

　　A) no one bas ever clearly known how he himself was bit

　　B) man tends to be subjective when he describes his encounter with a snake

　　C) the aggressiveness of the snakes differs according to diverse situations

　　D) a snake does not begin co attack without provocation

　　5. The author uses the example in the last paragraph m support his ideathat___________.

　　A) snakes do not begin the aggressive act if it is not disturbed

　　B) some snakes are more aggressive and more ready to attack

　　C) it is hard to forecast whether and how snakes would attack

　　D) snakes often conceal themselves as their principal defense