首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Bees that help with pollination benefit flowers and【L31】________. Bees produce wax that can be made into candles and【L32】_______
Bees that help with pollination benefit flowers and【L31】________. Bees produce wax that can be made into candles and【L32】_______
admin
2022-09-09
15
问题
Bees that help with pollination benefit flowers and【L31】________.
Bees produce wax that can be made into candles and【L32】________.
Dragonflies primarily eat【L33】________.
Insects in summer can be harmful because they can carry such deadly diseases as malaria,
yellow fever, and【L34】________.
Harmful insects may destroy crops, clothes, furniture, and even the【L35】________.
【L31】
Good afternoon, and welcome to Insect Biology 101. I’d like to begin this course with a few remarks about good insects and bad ones. Bugs are all around us and that’s both a benefit and an annoyance — sometimes maybe even serious harm. First, let’s talk about the good things that insects do for us.
Probably the most important insect for humans, and maybe for all other life, is the bee. Bees help plants in the process of pollination, and
thus are necessary to most flowers and fruit trees
. That is, they carry pollen from ‘male’ flowers to ‘female’. If it weren’t for bees, we’d have very few food plants and no fruit either. In fact, there would be no ‘we’. No less a thinker than Albert Einstein pointed out that, without bees, humanity would be dead within a year or less. We’d starve. It’s that simple. That should maybe make us just a little humble.
A little less dramatic is the fact that bees also make the honey we eat. Moreover,
they produce beeswax, which is useful in candles and it’s also used as a first-rate furniture polish
. Sure, these may not be vital to our lives, but they can serve as reminders of how important bees are. That’s a point I keep coming back to in this course. Though, in all fairness, I should point out that butterflies aid in pollination as well as bees.
Now, here in Michigan, what’s the worst part of summer? Yep, that’s right — mosquitoes. But I’m talking about helpful insects, right? So let’s look at the dragonfly first. If there were no dragonflies, there would be even more mosquitoes!
Dragonflies mainly eat mosquitoes and also a few other insects
. Yes, that’s right. They don’t just fly around, and they also help to eliminate harmful insects. So, the next time you see a dragonfly, don’t you dare kill it!
Now let’s talk a little about those harmful insects. Take the mosquitoes I just mentioned as an example. Not so many years ago, mosquitoes here in America weren’t just annoying. Some were even deadly. They carried malaria and yellow fever. My own ancestor, the Confederate General John Bell Hood, lived through the worst battles of Civil War only to die at age thirty-eight from yellow fever. A pest, not a bullet!
Well, besides the mosquitoes, in summer there is also a kind of insect that never seems tired. Right, that is the fly. Before I go on talking, I must mention an African fly called the Tsetse fly, which feeds on blood and can cause serious diseases in the people and animals that it bites.
Besides, it is still a bearer of sleeping sickness
, which affects around 300,000 people every year in Africa and can be treated only with toxic drugs that are hard to administer. Worse still, the drugs sometimes don’t work.
Other insects, of course, destroy food crops. In China, for instance, locusts continue to be a danger to the harvest in some areas. Less important, but still annoying, moths eat people’s clothes and dust mites slowly destroy carpets. Worse, but still in the home, termites or "white ants" eat wood — the wood of your house.
If they are not stopped, they can eventually destroy the whole building
. Usually, they seriously damage a building before anyone even notices them. So, as we all know, insects can be a real trouble.
For some decades in the West, to kill insects with chemicals seemed a good remedy. Unfortunately,
chemicals can only be used in a limited area for a limited time. It’s a small-scale solution
. The insects come back. Worse still, some of the poisons used like DDT were found harmful to the environment. Many kinds of wildlife, like hawks, were harmed. And people in chemical-using rural areas have one of the highest rates of liver cancer in the world.
It’s no secret that the chemicals remain harmful to humans
.
Like all species, insects adapt to their changing environments at an amazing rate. When a new chemical is introduced to their habitat, the insects that survive are generally the ones with some way of resisting the harmful effects. They then breed with the other survivors, and
just like that insects become resistant to most poison in a few generations
. An insect generation, remember, is a couple of months at most!
So, again we have to ask: what to do? Well, there are biological solutions. Some of these are pretty simple. One is destroying the insects’ habitat. You take away their home or food. Cleaning your kitchen is the best way to prevent roaches. No garbage: no food. Getting rid of marshes and swamps eliminates mosquitoes. Other solutions might include bringing in dragonflies or bats in areas where mosquitoes are many.
This is a cheaper alternative to chemicals
. Biological methods like this also bring no extra pollution to the environment. But you have to be careful. If you change the environment too much, you might be hurting other forms of life accidentally.
One recent method of controlling insect populations involves interrupting their breeding cycle. What does that mean? It means ‘birth control for bugs’. Insects are provided with food that makes them unable to reproduce. Since they can’t have babies, the population disappears, or nearly so. And since no young are born, resistance is not a problem with no young insects developing increased resistance.
Interrupt the life cycle, eliminate the bug!
It’s clear that we must have an understanding of the life cycle of the insect
. At least, that’s the plan. We’ll go into more details as this course goes along. Now I will stop here to see whether you have any questions or not.
选项
答案
fruit trees
解析
空格前为and,推测应填入和flowers并列的名词。录音原文中的help…pollination是的原词复现,录音中的are necessary to是benefit的替换表达,故空格处应填入fruit Wees。
转载请注明原文地址:https://jikaoti.com/ti/h6biFFFM
本试题收录于:
雅思听力题库雅思(IELTS)分类
0
雅思听力
雅思(IELTS)
相关试题推荐
有以下程序:#include<stdio.h>intfun(){staticintx=1:x*=2:retumx;}main(){inti,s=1:for(i=1;i<=3;i++)s*=fun();printf("%d\n
Whatisthemeetingabout?
PeopleallovertheworldknowWimbledonasthecentreoflawntennis.In1874itwasacountryvillage,butitwasthehome
Makinggoodchoicesaboutyourownhealthrequiresreasonableevaluation.Akeyfirststepinbetteringyourevaluationability
Travellingcanbeawonderfuladventure.Travellingbyairplane,however,canbeverytiring.Thefollowing【K1】________(be)s
Ibecameinterestedinwritingatanearlyage.Sowhenmyfourth-gradeteachertoldmeabouta【C1】________writer’sconferencew
Ibecameinterestedinwritingatanearlyage.Sowhenmyfourth-gradeteachertoldmeabouta【C1】________writer’sconferencew
WhatisDennis’opinionabouttherestaurant?
Whatcanbefoundoneachfloorofthearchivesbuilding?CITYARCHIVESAnineteenth-centurydocumentsBmapsCpersonalpaper
Scientistsfindthathard-workingpeoplelivemuchlongerthanaveragemenandwomen.Careerwomenarehealthierthanhousewives
随机试题
甲市A公司以信件方式向乙市B公司发出承诺通知。A公司于11月5日将信件送达甲市邮局,到达乙市邮局的日期为11月7日,该信送达B公司收发室的日期为11月8日,B公司总经理阅读该信件的日期为11月10日。A公司承诺生效的时间为
心肌抑制因子(MDF):
放疗、化疗后有关骨髓的描述正确的是
鳃裂囊肿穿刺液多为皮样囊肿穿刺物为
既可安神,又可祛痰的药物是()
甲公司预计2015年度持有的以公允价值进行后续计量的资产的公允价值将大幅度下降,为减少公允价值大幅度波动对公司损益的影响,甲公司决定进行如下会计政策变更。(1)2015年1月1日,甲公司将所持有乙公司股票从交易性金融资产重分类为可供出售金融资产,并将其作
根据所给材料处理问题。某期刊为16开本,在版式设计上既讲究原则性又倡导灵活性。某相关专业的大三学生小王到该期刊社实习,找了一篇名为《大数据重塑能源系统,智能管理的有效利用是重点》的文章练习版式设计。该作品的正文主体文字用10.5磅宋体,通栏排。按
教师职业专业化的条件是什么?
查询单价在600元以上的主机板和硬盘的正确命令是
A、Watersports.B、Racinginrivers.C、Storiesaboutwomenswimmers.D、Booksaboutswimming.D题干问的是最近什么流行起来了。短文中提到,人们常常把生命比作水,这可能
最新回复
(
0
)