题目内容
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（瓢虫）．Lady beetles are a natural control for aphids（蚜虫）．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 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．are more destructive than helpful．
分析 本文介绍了瓢虫，瓢虫的地理分布以及瓢虫的作用．许多著名的瓢虫都来自亚洲或欧洲，在美国很普遍，专家认为是瓢虫益大于弊，不应被视为害虫．
解答 5．B 细节理解题．根据文章第二段第二句"Lady beetles are red，orange or black"可知，瓢虫是红色的、橙色的或黑色的，故B项正确．
6．A 推理判断题．根据文章第四段第一句"American scientists imported one kind of lady beetle，the multicolored Asian lady beetle，as early as 1916．"可知，早在1916年初，美国科学家就引进了一种瓢虫，一种彩色亚洲瓢虫．自1916年至今应为90多年，但离一个世纪还有好几年，所以A项为最佳选项．
7．B 推理判断题．根据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，专家说，在美国北部发现了450多种瓢虫，有些是本地的，有些是从其他地方带来的，几乎所有的都对农民有帮助．B项"只有一些进口的瓢虫有助于当地的植物"与文章内容相悖，故选B．
8．A 细节理解题．根据末段最后一句"But they say theinsects are too helpful to be considered as pests．"可知，专家的观点是瓢虫益大于弊，不应被视为害虫，故选A．
点评 本文介绍了瓢虫，瓢虫的地理分布以及瓢虫的作用，专家认为是瓢虫益大于弊，不应被视为害虫．题目涉及细节理解题，做题时结合原文和题目有针对性地找出相关语句进行仔细分析，结合选项选出正确答案．推理判断题，在抓住关键句子的基础上进行合理正确的分析，切记胡乱猜测，做到有理有据．
