6．When a big boat，like a cruise ship，goes through the ocean，it often creates waves．This happens when the large engines on the back of the cruise ship cause the water on the ocean's surface move up and down violently．These waves move out from the boat in both directions．If you are captaining a smaller boat，you'd better steer clear of a ship's wake，so that your boat is not surfing on the waves，causing it to overturn
A wave is a pattern of motion．When you look at a wave，it may appear as simply water moving across the surface of the ocean．In fact，this is false．The water is actually not moving in the same direction as the wave．While the wave itself--the pattern of motion-is moving across the surface of the ocean，the water is actually moving in a circular motion，which brings the water molecules back to their original position．The water merely gives the appearance of moving forward．
If this is confusing，think of the kind of wave you do at a baseball stadium．Viewed from a distance，the wave is clearly moving across the stadium．But the thing that makes up the wave-the people-are not moving across the stadium，they're just moving up and down in their seats．This is just like the water in an ocean wave．A lot of water is moving up and down，which gives water the appearance of moving along with the wave．
Surfers pay a lot of attention to waves．If you're not in an area where the waves are suitable for surfing，then you can't surf．Usually，surfers gather in areas known for big waves-waves that rise high off the ocean's surface．If the wave is bigger，then the surfer is often able to surf for longer distances and perform more tricks．The height of a wave is known as its amplitude．If you could make a wave freeze，then you could measure the wave's amplitude by running a tape measure from the ocean's surface to the very peak of the wave．
All waves can be measured using amplitude and wavelength．While the waves created by a boat have very small amplitude-sometimes as small as a few centimeters-the wavelength can be very short，as lots of waves are being generated．By contrast，a tsunami has very high amplitude，sometimes more than 100feet，but a relatively long wavelength，as it's a high wave．
Waves generated in the same way can have great differences in amplitude and wavelength．For example，think back to the cruise ship．While each ship creates waves caused by the movement of the boat，the properties of each of the waves may be very different．For example，a larger cruise ship，with powerful engines，may create a wave that has high amplitude and a short wavelength．However，if the ship's engines slow down，they may then start creating less powerful waves at a slower rate．This would cause the waves'amplitude to decrease，but its wavelength to increase．
74．What does the phrase"steer clear of a cruise ship's wake"in the 1st paragraph meanC？
A．keep awake while steering a ship
B．get a clear view of what is ahead
C．keep away from the cruise ship
D．follow the cruise ship very closely
75．The author gives an example of wave people do in the stadium in order toD．
A．illustrate how excited people are in a basketball stadium
B．clear the confusion over measuring the wave's amplitude
C．demonstrate how to make waves in a basketball stadium
D．explain why the water appears to move along the waves
76．The last paragraph gives us the impression thatB．
A．the wave's amplitude may vary，but its wavelength remain the same
B．the move powerful the ships engines are，the higher the waves they generate
C．the amplitude of a wave depends on the direction the water moves forward
D．measuring the amplitude and wavelength of waves is not quite easy
77．What is this passage mainly aboutA？
A．How waves are created and measured．
B．What makes the sea water move forwards．
C．Why people create waves in the stadium．
D．How to steer a cruise ship in the rough sea．
分析 这篇文章谈论的是关于水波的，讲到水波是如何产生和水波如何测量的科学知识．
解答 74-77 CDBA
74．答案 C 细节理解 这道题目稍微有点难度，需要学生理解上下文之后搞清楚：如果你开的是较小的船，那么为了不翻船，最好不要靠近较大的船只．故答案为C
75．答案 D 段落理解 这道题目难度不大，作者举了在体育场的人们发出的波动的例子，是为了更形象地说明水和水波同时出现并向前进．故答案为D
76．答案 B 段落理解 难度适中．最后一段的第一句话就表明了这一段主要讲的是波纹也是不同的，"For example，a larger cruise ship，with powerful engines，may create a wave that has high amplitude and a short wavelength"这句话也说明引擎越有力，波浪就越高．故答案为B
77．答案 A 主旨大意 难度适中．整篇文章谈论的都是关于水波的，从它的产生到最后一段讲的如何测量．故答案为A
点评 1、要想做好科普英语阅读理解题，同学们就要注意平时多读科普知识类文章，学习科普知识，积累常见的科普词汇，从根本上提高科普英语的阅读能力．
2、要熟悉科普类文章的结构特点．科普类文章一般由标题（Head line），导语（Introduction），背景（Back ground），主体（Main body）和结尾（End）五部分构成．标题是文章中心思想高度而又精辟的概括，但根据历年的高考情况来看，这类阅读理解材料一般不给标题，而要同学们选择标题．导语一般位于整篇文章的首段．背景交待一个事实的起因．主体则对导语概括的事实进行详细叙述，这一部分命题往往最多，因此，阅读时，同学们要把这部分作为重点．结尾往往也是中心思想的概括，并与导语相呼应，命题者常在此要设计一道推理判断题．
3、在进行推理判断时，同学们一定要以阅读材料所提供的科学事实为依据，同时所得出的结论还应符合基本的科普常识．
