TPO66听力Lecture1听力原文+题目+答案+MP3下载

TPO66听力Lecture1听力原文+题目+答案+MP3下载

TPO66听力Lecture1听力原文

Listen to part of a lecture in a biology class.

Okay.Today I want to talk about sleep.We all sleep.Humans sleep.Many animals sleep.When we sleep,we aren't actually unconscious,but in a state of reduced awareness of our surroundings.Now,what does that mean for animals in the wild if they are in a state like that unable to monitor their environment?

Well,they are helpless,vulnerable to predators maybe.Right,they are vulnerable to predators,yet they sleep,so let's talk about why,the biology of sleep.So the first thing I want you to understand is that sleeps are very risky behavior.And risky behaviors don't evolve unless they bring the animal some kind of benefit that outweighs that risk.Sleep must have a really important function.

And I want to emphasize that there is a difference between sleep and other forms of inactivity,like regular rest.Insects,for instance,rest,but they don't sleep.What's specific to sleep is that the brain alters many ofits usual activities including its connection to sensory and motor organs.It shuts those connections down,so a sleeping animal can usually neither sense nor move.I say usually because,well,we'll get to that in a minute.

So basically all mammals and birds sleep,but there are some unusual ways of sleeping.Take marine mammals,like dolphins.Dolphins need to swim up for air once in a while,so they can't completely shut off all movement and sensation,so their brain can't shut down completely,but dolphins get around this.How?

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TPO66Lecture1听力题目，一共有6道题，具体如下：

1. What is the main purpose of the lecture?

A. To highlight the dangers fish encounter

B. To compare the movement of fish and humans

C. To discuss the function of certain fish fins

D. To show the way in which fish fins have evolved
 

2. According to the professor, what problem do requiem sharks have when swimming?

A. Their large fins cause decreased buoyancy.

B. Their fins do not function well as brakes.

C. They cannot make sharp turns.

D. They are unable to accelerate rapidly.
 

3. How does the professor illustrate the meaning of the term “drag”?

A. By describing the movement of arms and legs

B. By mentioning the case of the propeller

C. By explaining how fish escape from predators

D. By comparing it to the force of air on an airplane
 

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