16．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 floating in the water，the researchers said they hear sound waves that tell them the type and amount of contamination （致污物） 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 （水生生物學(xué)家） at Israel's Bar Ilan University．"Algae is the first thing to be affected by a change in water quality．""The secret，"he said，"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 （過于豐富） of algae in the planet's water．Most of the oxygen in the atmosphere comes from algae．A prototype tester （樣本測(cè)試機(jī)）that occupies about one square meter of a laboratory desktop，shoots a laser beam at water samples to stimulate （刺激） 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．She said that testing algae photosynthesis can determine water quality more accurately and easily than labor-intensive methods now used like chemical and radioactive carbon testing．
5．The underlined word"algae"in Paragraph 2probably refers to a kind ofA．
A．plant B．instrument
C．wood D．pollutant
6．Why is the algae tested？B
A．Because it floats on the water．
B．Because it is the first to be polluted．
C．Because it can have photosynthesis．
D．Because it can produce different sounds．
7．We can infer from the passage thatC．
A．a(chǎn)lgae can produce a loud sound when polluted
B．a(chǎn)lgae can die easily from pollution
C．photosynthesis of the algae is related to water quality
D．photosynthesis of the algae can only be caused by sunlight
8．What would be the best title for the passage？D
A．The Problem of Chemical and Radioactive Carbon Testing
B．A Prototype Tester Is Used to Determine Water Pollution
C．The Importance of Photosynthesis of the Algae
D．Scientists Listen to Plants to Find Water Pollution．
分析 本文是一篇科教類閱讀，屬于說明文，以色列的科學(xué)家們發(fā)現(xiàn)了一種通過"傾聽"水中植物的說法來測(cè)試水污染的新方式．本文以此展開講述，主要講了科學(xué)家通過探聽水中植物的狀況來發(fā)現(xiàn)水污染的程度．
解答 5．A．詞義猜測(cè)題．由文章第一句中的"what the plants"及第三段倒數(shù)第二句中"meaning the plant's ability to transform light into energy"可推出，algae是一種植物，因?yàn)橹挥兄参锊拍苓M(jìn)行光合作用．故選A．
6．B．細(xì)節(jié)理解題．由文章第三段第二句Algae is the first thing to be affected by a change in water quality可知，藻類是水中最先受到污染的植物，因此科學(xué)家用它來研究并判斷水的污染情況．故選B．
7．C．推理判斷題．由文章最后一段She said that testing algae photosynthesis can determine water quality more accurately and easily than labor-intensive methods now used like chemical and radioactive carbon testing．可知，通過檢測(cè)藻類的光合作用可以確定水的質(zhì)量，因此藻類的光合作用跟水的質(zhì)量有密切關(guān)聯(lián)．故選C．
8．D．主旨大意題．概括全文可知，本文主要講了科學(xué)家通過探聽水中植物的狀況來發(fā)現(xiàn)水污染的程度．文章第一段就點(diǎn)明了主旨．故選D．
點(diǎn)評(píng) 本文是一篇科教類閱讀，題目涉及多道細(xì)節(jié)理解題，詞義猜測(cè)題，主旨大意題．做題時(shí)學(xué)生應(yīng)仔細(xì)閱讀原文，把握文章主要內(nèi)容，聯(lián)系文章上下文內(nèi)容并結(jié)合所給選項(xiàng)含義，從中選出正確答案，一定要做到有理有據(jù)，切忌胡亂猜測(cè)．
