Question

At night, bats fly through the air, catching hundreds of insects and other small animals. But during the day, they hardly move at all. Instead, bats pass the time hanging upside down from a secret spot.

There are a couple of reasons why bats rest this way. First of all, it puts them in a position for takeoff. Unlike birds, bats can’t fly into the air from the ground. Their wings don’t produce enough lift to take off from a dead stop, and their hind legs are so small and underdeveloped that they can’t run to build up the necessary takeoff speed. Instead, they use their front claws to climb to a high spot, and then fall into flight.

During the hours when most enemies are active, bats gather where few animals would think to look and most can’t reach. This allows them to disappear from the world until night comes again. There’s also little competition for these resting spots, as other flying animals don’t have the ability to hang upside down. Bats have a unique physiological adaptation that lets them hang around this way without using any energy. For you to hold your fist around an object tight, you contract(紧缩) several muscles in your arm, which are connected to your fingers by tendons(腱)；as one muscle contracts, it pulls a tendon, which pulls one of your fingers closed. A bat’s talons(爪) close in the same way, except that their tendons are connected only to the upper body, not to a muscle. To hang upside down, a bat pulls its claws open with other muscles. To get the talons to take hold of the surface, the bat simply lets its body relax. The weight of the upper body pulls down on the tendons connected to the talons, causing them to hold tight. Therefore, the bat doesn’t have to do anything to hang upside down.

1.Bats hang upside down because________.

A. they haven’t developed a pair of strong claws

B. they can’t start to fly from the ground directly

C. they have no hind legs to support their body

D. they can’t find quiet places to stay during the day

2.The third paragraph tells us that bats’ hanging upside down_______.

A. is to save their energy for night movement

B. is a way to fight against flying animals

C. is a great way to hide from danger

D. is a skill to compete for the flying places

3.Why can bats hang upside down easily?

A. Because their upper body is light.

B. Because they have strong muscles.

C. Because their talons are linked to muscles tightly.

D. Because their tendons are linked to their upper body.

4.What is the passage mainly about?

A. The living habits of bats.

B. How and why bats hang upside down.

C. The importance of bats’ hanging upside down.

D. How bats use their energy at night.

Answer

1.B

2.C

3.D

4.B

【解析】

试题分析：蝙蝠晚上在空中飞舞，捕捉小虫子和其它的小动物，白天却几乎不动，倒挂在一个隐秘的地方。蝙蝠为什么这样休息呢?这有好几个原因。其一，是为了让自己处在一个起飞的位置；其二，是为了防备敌人。

1.细节理解题。从第二段it puts them in a position for takeoff. Unlike birds, bats can’t fly into the air from the ground.它可以让它们处在一个起飞的位置，蝙蝠不像其它的鸟一样可以从地面起飞。故选B。

2.推理判断题。根据第三段During the hours when most enemies are active, bats gather where few animals would think to look and most can’t reach.，在大多数敌人很活跃的时候，蝙蝠躲在一个极少动物会认为需要查看或是大多数够不着的地方。other flying animals don’t have the ability to hang upside down其它飞行动物都没有倒挂的能力，可知倒挂的这种休息方式是很好的躲避敌人的办法。故选C。

3.细节理解题。根据第三段倒数第四行their tendons are connected only to the upper body, not to a muscle.它们的腱只跟上面的身体连在一起，而不跟肌肉相连。故选D。

4.主旨大意题。根据第二段第一句There are a couple of reasons why bats rest this way蝙蝠为什么这样休息有好几个原因可知。故选B。

考点：考查科教类短文阅读。