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
2022-03-30
54
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】________
How to Kill Bad Insects
Chemical Methods
These solutions to insect problems are often not worthwhile because:
a) They are effective on a【L36】________
b) They can bring harm to【L37】________.
c) Insects become【L38】________to the chemicals quickly.
Biological Methods
These Methods are【L39】________ than chemical methods of eliminating harmful insects.
Breeding Control Methods
In order to control the breeding of insects, one needs to understand the insects’ 【L40】________
【L33】
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
mosquitoes
解析
空格前为eat,推测应填入某种昆虫的食物。录音原文中的mainly与题目的primarily属于同义替换,故空格处应填入mosquitoes。
转载请注明原文地址:https://kaotiyun.com/show/3e8O777K
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
In2007,whatconclusiondidgamesproducersatNickelodeoncometo?
ChooseTWOletters,A-E.Writethecorrectlettersinboxes21and22onyouranswersheetWhichTWOofthefollowingbenefitsa
About60%ofpeoplewhouseonlinenetworkingsitesareconcernedthattheirpersonaldetailsmaybeaccessibletopeopletheyd
personaland/orfinancial
Completetheform.WriteNOMORETHANTHREEWORDSforeachanswer.PERSONALDETAILSFORMName:Mary【T6】______Address:Flat2【T
WhichTWOofthefollowingcanyougetadviceaboutfromtheUnion?(A)immigration(B)grants(C)medicalproblems(D)personalpro
WhichTWOofthefollowingcanyougetadviceaboutfromtheUnion?(A)immigration(B)grants(C)medicalproblems(D)personalpro
Completethenotesbelow.WriteNOMORETHANTHREEWORDSforeachanswer.PersonalityQuestionnairescom
随机试题
随机抽样调查是指按照随机原则从总体中抽取部分单位构成样本,以样本数量信息推断总体数量特征的调查。按随机抽选的方式划分有()。
泵是化工厂主要流体输送机械。泵的选型通常要依据流体的物理化学特性进行。下列关于泵的选型要求的说法中,正确的是()。
价值工程的工作程序是( )。
根据政府采购法律制度的规定,在政府采购中,经采购入同意,供应商可以依法采取分包方式履行合同。对于分包项目的履行,下列表述中,正确的是()。
甲在离家不远的一偏僻处发现自己的女友正在遭受两男青年丙和丁的挑逗侮辱,便前去呵斥,但遭丙、丁的殴打,甲被迫还手。在对打时,一便衣警察戊路过,见状即抓住甲的左肩,但未表明其警察身份。甲误认为戊是对方的帮凶,便掏出匕首朝戊右臂刺去,造成戊轻伤。甲见状逃跑。本案
影响劳动生产率的主要因素有
在面向对象技术中,类属是一种(35)机制。一个类属类是关于一组类的一个特性抽象,它强调的是这些类的成员特征中与(36)的那些部分,而用变元来表示与(37)的那些部分。
张经理在对Word文档格式的工作报告修改过程中,希望在原始文档显示其修改的内容和状态,最优的操作方法是:
A、小刘B、小王C、小李D、小汪D
Nowadays,somethinghasgoneterriblywrongwithouronce-proudAmericanwayoflife.Ithashappenedintheareaof【C1】______A
最新回复
(
0
)