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  • Fish Movement托福听力原文翻译及问题答案

    时间:2023-07-09 12:44:53 来源:www.ivyeducation.cn

    Fish Movement托福听力原文翻译及问题答案,今天常春藤就来为大家分析这个问题。

    一、Fish Movement托福听力原文:

    So we’ll continue today with the topic of fish movement and we'll focus on the role of fins.You can think of things pretty much like the arms and legs of humans.It‘s what allows movement basically.But as we will see they also do a lot more.Before we go on with the function of specific fins,I just say a few general remarks.So you get an overall picture.Fins are mainly used for moving the fish forward for propulsion as it's called,but they’re also needed for stability,steering and braking.That's right.Fish have to have a way to put on the brakes too.

    Now,some fish are so fast,they‘re not good at stopping even with their fins.Requiem sharks,for example.You know,how sharks are built for speed.But these requiem sharks have difficulty stopping.They're unable to brake themselves efficiently,so they must take sharp turns in order to slow down or stop.Because of this,hmm,this brake problem.Requiem sharks avoid swimming into coral reefs.Coral reefs are usually crowded,don't allow a lot of space for large fish to take sharp turns.So these sharks roam around the outside of the coral reefs.

    Um,a fish lives in a 3 dimensional world,you know,with forces pushing and pulling it in all directions.The forces in referring to are gravity,which pulls the fish downward.Buoyancy,which holds it up in the water,and something called drag.

    Now,drag means to slow down,to impede movement.It's a term that applies to the effect of the force acting on any object moving through a fluid or through air.So for instance,the force of air on an airplane,drag acts to pull the airplane in the opposite direction to the direction of motion.

    Well,all of these forces,gravity,buoyancy,and drag could be potentially dangerous for fish if they weren't for the fact that they have.Yep,you guessed it,fins.So,fins allow fish to keep from rolling or flipping over.They stabilize the fish's head.

    Fins are crucial for determining the speed at which fish travel,to change direction.In a word,fins allow the fish to maneuver efficiently through the water.Okay.Remember,most fish have two general types of fins.

    The first type is median fins.Median fins are located along the midline of the fish such as the dorsals on the back.And the caudal fins,the tail fin.The other type of fin is the paired fins at each side of the fish.

    For today,the caudal fin is the one will focus on.The caudal fin,that is the tail fin.Is the main propulsive agent for most fish,it keeps them moving forward.Some fish have a broad tail that gives the fish a quick burst of speed from a standing position.And this is useful for going after a meal or swimming away from a predator.

    You'll find that fast,long distance swimmers have a very long and narrow caudal fin,which is very efficient.Now,do all fish have caudal fins?No,not at all.Some sea horses and eels get along without them just fine.Well,a seahorse swims in an upright vertical position.It looks like its standing up,right.So it uses a fin on its back,the dorsal fin,as if it were a caudal fin.

    And eels,well,don't really need to swim very rapidly.And like l said,most are missing the caudal fin,but most fish do have caudal fins.I give you two examples of caudal fins,and well see how they work.Okay?Let's see.I focus on the tuna and the black fish.The tuna's body is built for speed,but the caudal in,the caudal fin is key here because its moon-shaped tail creates hardly any drag in the water.And it can reach really high speeds of even 60 to 80 kilometers per hour and that's pretty amazing.

    Then there's the really interesting case of the blackfish,which has a rounded caudal fin.As you can see.And in sudden bursts,it almost acts like a propeller on a plane that can even produce the sound that as an explosion.I bet you never thought of fish fin could do that.And you can see how this is useful to a fish when it goes to catch something or tries to avoid a predator.It needs to accelerate in an instant.

    二、Fish Movement托福听力中文翻译:












    三、Fish Movement托福听力问题:

    Q1: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

    Q2:According to the professor,what problem do requiem sharks have when swimming?

    A.Their large fins cause decreased bouyancy.

    B.Their fins do not function well as brakes.

    C.They cannot make sharp turns.

    D.They are unable to accelerate rapidly.

    Q3: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

    Q4:Why does the professor mention sea horses and eels?

    A.To illustrate that not all fish have a caudal fin

    B.To give an example of buoyancy

    C.To discuss long-distance swimmers

    D.To show how long,narrow tail fins function

    Q5:According to the professor,what do rounded caudal fins allow the fish to do?

    A.To brake more effectively

    B.To keep their balance

    C.To gain speed rapidly

    D.To change direction

    Q6:Why does the professor say this:

    A.She wants the students to make predictions on the speed of fish.

    B.She wants to show how fish communicate with one another.

    C.She thinks the students have not read the textbook thoroughly.

    D.She wants to convey the extraordinary power of some fins.

    四、Fish Movement托福听力答案:








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