16.There are lots of insects that farmers hate.But there also are some they like.These protect crops against damage from other insects.A good example is the lady beetle,which is also known as the ladybug(瓢蟲).
Lady beetles are a natural control for aphids(蚜蟲).Lady beetles are red,orange or black.They often have black spots,though some have light colored spots.Different kinds of lady beetles have different numbers of spots.There are lady beetles with four,five,seven and fourteen spots.
Many of the well-known kinds of lady beetles come from Asia or Europe.They now are common throughout the United States.
American scientists imported one kind of lady beetle,the multicolored Asian lady beetle,as early as 1916.They released them as an attempt to control some kinds of insects.Over the years,the beetle has become established,possibly helped by some that arrived with imported plants on ships.
Experts say over 450kinds of lady beetles are found in North America.Some are native to the area.Others have been brought from other places.Almost all are helpful to farmers.
The Asian lady beetles now in the United States probably came from Japan.The Asian lady beetle eats aphids that damage crops like soybeans,fruits and berries.
In the southern United States,Asian lady beetles have reduced the need for farmers to use pest-killing poisons on pecan trees.This popular tree nut suffers from aphids and other pests that the lady beetles eat.
But some people say the Asian lady beetle has itself become a pest.They worry that the lady beetles may eat their late-autumn fruit crops.
Experts say Asian lady beetles may appear in large numbers in some years.But they say the insects are too helpful to be considered as pests.
5.What do ladybugs look like?B
A.All kinds of ladybugs are of the same color.
B.Most of them are red,orange or black.
C.They each have the same number of spots on them.
D.Most of them have fourteen spots.
6.Asian ladybugs have been in the United States forA.
A.over nine decades
B.hundreds of years
C.half a century
D.a(chǎn) century
7.According to the passage the following statements are supported EXCEPTB.
A.there are more than 450kinds of ladybugs in North America,including native ones
B.only some imported ladybugs are helpful to the local plants
C.soybeans,fruits and berries are favorites of aphids
D.pecan trees are common in the south of America
8.According to the experts,ladybugs areA.
A.more helpful than considered as pests
B.more pests than helpful insects
C.helpful as well as destructive
D.a(chǎn)re more destructive than helpful.
分析 本文介紹了瓢蟲,瓢蟲的地理分布以及瓢蟲的作用.許多著名的瓢蟲都來自亞洲或歐洲,在美國很普遍,專家認為是瓢蟲益大于弊,不應被視為害蟲.
解答 5.B 細節(jié)理解題.根據(jù)文章第二段第二句"Lady beetles are red,orange or black"可知,瓢蟲是紅色的、橙色的或黑色的,故B項正確.
6.A 推理判斷題.根據(jù)文章第四段第一句"American scientists imported one kind of lady beetle,the multicolored Asian lady beetle,as early as 1916."可知,早在1916年初,美國科學家就引進了一種瓢蟲,一種彩色亞洲瓢蟲.自1916年至今應為90多年,但離一個世紀還有好幾年,所以A項為最佳選項.
7.B 推理判斷題.根據(jù)文章第五段最后一句"Experts say over450kinds of lady beetles are found in North America.Some are native to the area.Others have beenbrought from other places.Almost all are helpfulto farmers."可知,專家說,在美國北部發(fā)現(xiàn)了450多種瓢蟲,有些是本地的,有些是從其他地方帶來的,幾乎所有的都對農(nóng)民有幫助.B項"只有一些進口的瓢蟲有助于當?shù)氐闹参?與文章內(nèi)容相悖,故選B.
8.A 細節(jié)理解題.根據(jù)末段最后一句"But they say theinsects are too helpful to be considered as pests."可知,專家的觀點是瓢蟲益大于弊,不應被視為害蟲,故選A.
點評 本文介紹了瓢蟲,瓢蟲的地理分布以及瓢蟲的作用,專家認為是瓢蟲益大于弊,不應被視為害蟲.題目涉及細節(jié)理解題,做題時結(jié)合原文和題目有針對性地找出相關(guān)語句進行仔細分析,結(jié)合選項選出正確答案.推理判斷題,在抓住關(guān)鍵句子的基礎上進行合理正確的分析,切記胡亂猜測,做到有理有據(jù).