Scientists in Israel have discovered a new way to test for water pollution by "listening" to what the plants growing in water have to say．By shining a laser beam(激光束) on the tiny pieces of algae(海藻) floating in the water, the researchers said they hear sound waves that tell them the type and amount of pollution in the water．

"It is a red light, telling us that something is beginning to go wrong with the quality of water," said Zvy Dubinsky, an aquatic biologist at Israel's Bar Ilan University．"Algae is the first thing to be affected by a change in water quality．"

As water sources deteriorate worldwide, the testing of algae could be used to monitor water quality faster, more cheaply and more accurately than techniques now in use, Dubinsky said．The secret is to measure the rate of photosynthesis(光合作用) in the algae, meaning the plant's ability to transform light into energy．During photosynthesis, plants also release oxygen into the air．

Dubinsky's technique is easy to perform because of the over-abundance of algae in the planet's water．Most of the oxygen in the atmosphere comes from algae．A prototype tester shoots a laser beam at water samples to stimulate photosynthesis in the algae．But not all of the laser's heat is used．

Depending on the condition of the algae and the rate of photosynthesis, some of the heat is shot back into the water, creating sound waves, Dubinsky said．With a special underwater microphone, researchers are able to analyze the strength of the sound waves and determine the health of the algae and the condition of the surrounding water．

"Algae suffering from lead poisoning, like waste discharged from battery and paint manufacturing plants, will produce a different sound than those suffering from lack of iron or exposure to other toxins," said researcher Yulia Pinchasov．

72．To study water quality, scientists choose algae mainly because        ．

A．a(chǎn)lgae is most easily affected by pollution

B．most oxygen is produced by algae

C．the amount of algae is decreasing

D．a(chǎn)lgae is a kind of plant floating in the water

73．When Dubinsky studied water quality, he mainly focused on        ．

A．the amount of laser used by algae

B．the rate of photosynthesis in the algae

C．the condition of the algae

D．the heat of laser used by algae

74．After the study, scientists proved that        ．

A．the increase in population is caused by lack of water

B．global warming causes water resources to reduce worldwide

C．a(chǎn)lgae can show the type and amount of pollution in the water

D．a(chǎn)lgae is dying out in the ocean around the world

75．What would be the most suitable title for the passage?

A．Water pollution is reduced with the growth of algae

B．Pollution makes it hard for plants to make photosynthesis

C．Water pollution affects the growth of marine plants

D．Scientists listen to plants to find pollution

---It’s too hard．I can’t figure it out, Mommy.

--- _______, Tommy．You can make it!

       A．No problem          B．No hurry       C．Come on        D．That’s OK

—Such a mistake could have been avoided.

   —Unfortunately, he _______ the mistake again and again.

   A．repeated　　　　　　　　　　     B. would repeat

   C．had repeated　　　　　　　　      D. would have repeated

    It is well that young men should begin at the beginning and occupy the least important positions．21  of the leading businessmen of Pittsburgh had a serious responsibility placed upon them at the very  22  of their career．They were  23  to the broom(掃帚), spending the first hours of their business lives   24  the office．

And here is the basic  25  of success, the great secret:  26  your energy, thought, and capital (資本) wholly on the business in which you are  27  ．Having begun in one line, determine to fight it out on that  28  , to lead in it, adopt every  29  , have the best machinery, and know the most about it．

   The companies which fail are those which have 30  their capital, which means that they have scattered their brains  31   ．They have investments in this, or that, or  32  , here, there, and everywhere．“Don't put all your eggs in one basket” is all  33  , I tell you．“Put all your eggs in one basket, and then  34  that basket”．Look round you and take  35  ; men who do that do not often fail．It is easy to watch and carry the one basket．It is trying to carry too many baskets  36  breaks most eggs in this country．He who  37  three baskets must put one on his  38   , which is likely to fall down．One  39  of the American businessman is lack of concentration．

Remember: put all your eggs in one basket, and watch that basket． 40  Emerson says, "no one can cheat you out of final success but yourselves．"

21．A．None          B．Few               C．All           D．Many

22．A．beginning       B．end             C．point             D．promotion

23．A．ordered        B．promoted             C．introduced              D．stated

24．A．sweeping out   B．taking out      C．bringing out        D．picking out

25．A．inspiration      B．condition             C．plan               D．case

26．A．concentrate     B．devote              C．a(chǎn)pply        D．bury

27．A．charged         B．engaged             C．prepared     D．done

28．A．position       B．career             C．row           D．line

29．A．improvement   B．chance             C．learning      D．rise

30．A．gathered     B．forbidden           C．got           D．scattered

31．A．a(chǎn)lso           B．either            C．neither         D．yet

32．A．one             B．the other          C．others       D．the others

33．A．a(chǎn)pparent       B．clear              C．wrong       D．perfect

34．A．notice       B．observe             C．stare          D．watch

35．A．notice         B．comment           C．interest        D．concentration

36．A．what           B．that                C．whoever       D．whichever

37．A．brings          B．takes               C．carries       D．owns

38．A．mind          B．brain               C．head          D．hand

39．A．fault           B．a(chǎn)dvantage           C．pattern        D．model

40．A．When          B．While               C．Which       D．As

—What do you think of Andrew ?

   —There are some things that are not easy to         , and his coldness is one .

   A. put aside     B．put up with     C．think of   D．get along with

—So how is your new roommate?

   —She really _____. She’s always making loud noises at midnight and when I remind her,she always makes rude remarks.

   A. turns me off     B. turns  me  down    C. turns me out      D. turns me over

Jane was so         for the news of her lost child that she was almost driven          .

   A. proper , madly    B．thirsty , mad    C. sad , madly       D．curious , mad

A successful scientist needs _____ if he wants to make hypothesis (假設(shè)) of how processes work and how events take place.

　　A. permission     B. penetration

　　C. imagination    D. convention

John always tries to _____ people who are useful to him professionally.

　　A. develop B. provoke C. correspond  D. cultivate

He _____ the place where he had been bitten by an insect.

　　A. snatched B. scratched  C. squeezed  D. stretched