.

These achievements_______ without the contribution of Qian Xuesen, a key leader of the New China's nuclear, missile and so on．

       A．would have been unthinkable        B．would not be unthinkable

       C．would be unthinkable      D．would not have been unthinkable

練習(xí)冊系列答案
相關(guān)習(xí)題

科目：高中英語 來源：2011-2012學(xué)年上海市理工大學(xué)附屬中學(xué)高二下學(xué)期期末考試英語試卷（帶解析） 題型：填空題

ABCD請按實際情況填寫。其他請參照下表填寫。
A, B, C, D, E(AB), F(AC)

A. Control of Respiration
B. Basic tips for preserving cut flowers
C. Role of Respiration
D. Most Important Aspect of Flower Care
E. Need for Clean Water
F. Ways of Stopping Respiration
【小題1】
While everybody enjoys fresh cut flowers around his house, few people know how to keep them for as long as possible. This may be done by keeping in mind a few simple facts. The key to keeping fresh cut flowers for a week or more without floral preservatives(which contain biocides that kill bacteria and fungus) is to keep the water fresh and the stems free of air pockets so they can continue to draw up water.
【小題2】
An important thing to remember about cut flowers is that they are sensitive to temperature. For example, studies have shown that cut carnations(康乃馨) retain their freshness eight times longer when kept at 12℃ than when kept at 26℃. Keeping freshly harvested flowers at the right temperatures is probably the most important aspect of flower care.
【小題3】
Flowers are not intended by nature to live very long. Their biological purpose is simply to attract birds or insects, such as bees, for pollination (授粉). After that, they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide, called respiration (呼吸), generates the energy the flower needs to give the flower its shape and colour. The making of seeds also depends on this energy. While all living things respire, flowers have a high level of respiration. A result of all this respiration is heat, and for flowers the level of heat relative to the mass of the flower is very high. Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration, the sooner the flower dies.
【小題4】
How, then, to control the rate at which flowers die? By controlling respiration. How is respiration controlled? By controlling temperature. We know that respiration produces heat, but the reverse is also true. Thus by maintaining low temperatures, respiration is reduced and the cut flower will age more slowly.
【小題5】
Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to “drink” water that is dirty or otherwise polluted. Even when water looks and smells clean, it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach (含氯漂白劑) can be used in small quantities. It is recommended that 15 drops of chlorine bleach(at 4% solution) be added to each litre of water. The water and solution should also be replaced each day.

查看答案和解析>>

科目：高中英語 來源：2014屆江蘇南京高三9月學(xué)情調(diào)研英語卷（解析版） 題型：閱讀理解

 

 

The Green Microgym in Portland，Oregon has all the usual stuff you'd expect-sweaty people，loud music，smooth exercise equipment-but it has some extras as well. Everywhere you look，there are power wires. And these aren't the typical kind that let you surf the Web while you ride a spin cycle-although. you can do that too．The gym uses special exercise equipment that captures（捕獲）the energy you create while riding, converts（轉(zhuǎn)換）it into electricity and channels it into the power outlets（插座）．

The idea of using exercise equipment to produce electricity is not new. A gym in Hong Kong has been doing this since 2007. But clean (and healthy）energy is just now starting to catch on in U. S. gyms·"We have seen a significant increase in interest in the past six months，which is a good sign that fitness centers are ready to spend money on green technologies，” says Mike Curnyn，co-founder of the Green Revolution，a Connecticut-based firm that wires bikes into a central battery that can store energy.

The Green Microgym，first opened in 2008，has more than 200 members and is doing so well that owner Adam Boesel opened another one five miles from the original．Although membership costs about the same as ordinary gyms，customers can earn gift certificates from local businesses for watts produced while exercising．An average workout creates 37. 5 watt hours，which is enough to power a phone for a week．

Boesel uses spin bikes made by Resource Fitness，a Seattle company he co-owns，that captures energy produced from the flywheel. Wires send the converted AC current（交流電流） into any standard wall outlet-for this reason，the product line's name is Plug Out-and the energy created is used before the building draws power from the grid（電網(wǎng)）．Unlike the Green Revolution equipment，Plug Out machines cannot store extra energy. A third company，the Florida-based ReRev，is adding converters to a specific brand of spin bikes. But since the converters add＄1，000 to the price of the equipment，the ReRev and Green Revolution machines are at a disadvantage．

Resource Fitness，by contrast，sells its equipment for the same＄1，200 price as non- electricity-producing machines，removing the question of how long it will be until the energy savings pay for the cost of the unit．The company can afford to do this because its designs don’t call for the extra wiring needed for battery packs and large converters．It is also trying to price competitively with standard equipment so more gyms-and gym goers-will make the switch．

1.Members of the Green Microgym earn gift certificates for_______．

A .using the man-powered exercise equipment

B. saving electricity for local businesses

C. producing green electricity to power their phones

D. paying higher membership fees

2.The spin bikes made by Resource Fitness are different from those by Green Revolution in that_______.

A. they are easier to ride

B. they are more expensive

C. they don't have wires connected

D. they can not store extra electricity

3.What might prevent the green exercise equipment from getting more popular？

A .People's unwillingness to go green．

B. The high cost of making it.

C. Safety problems concerning electricity.

D. Lack of certificates．

4.The underlined words“make the switch”in the last paragraph most probably mean_____.

A. change to a different gym

B. use green exercise equipment

C. switch on the spin bikes

D. add a battery to the machine

 

查看答案和解析>>

科目：高中英語 來源：2013屆上海市高二下學(xué)期期末考試英語試卷（解析版） 題型：單詞拼寫

ABCD請按實際情況填寫。其他請參照下表填寫。

A, B, C, D, E(AB), F(AC), G(AD), H(BC), I(BD), J(CD)

A. assisting     B. essential     C. gain

D. individuals   E. gradually     F. struggle

G. connect      H. numerous     I. threats          J. enhance

  The recent bush fire showed yet again how well the citizens work together in the face of community ___1____. Yet sadly, when it comes to fighting less noticeable community problems, it can be a ___2_____ to pull together in the same way.

Community problems, such as unemployment, homelessness, depressions and social isolation, are caused by a wide range of factors and take a long time to fix. In the past, it’s often been up to ___3____ rather than communities to solve these problems. But this is ___4____ changing.

Communities are now being called on to get involved in “community building” activities which aim to __5____ people and their existing communities through an increased involvement in social activities, as well as getting unemployed people back to work or starting their own business.

The government offices have __6____ projects operating across the country, which are helping people to rebuild their lives and communities.

At the heart of strong communities are strong families, so much such work is focused on ___7____ children, young people and their families. However, they still have an enormous commitment to help people who are homeless. They also work hard to place people into jobs, helping them ___8____ the training, skills and self-confidence they need to find work or start their own small business.

Working in partnership with other organizations, the government offices provided a wide range of ___9____ service and long-term programs, which are achieving impressive results around the whole country.

 

查看答案和解析>>

科目：高中英語 來源：河北省09-10學(xué)年高一下學(xué)期第一次月考（英語） 題型：其他題

根據(jù)對話內(nèi)容，從對話后的選項中選出能填入空白處的最佳選項。選項中有兩項為多余選項。(注意：61-65的答案涂到答題卡上：E涂成 AB；F涂成AC；G涂成A

A．

A: Oh, you didn’t know how many people there were in the streets when I went shopping last Sunday!

B: No wonder. __61__ The earth will be full of people and there will be standing room only.

A: You said it.

B: __62__

A: Look up into the sky. What can you see?

B: __63__

A: The moon is the satellite of the earth, maybe man will fly to the moon.

B: __64__

A: I mean perhaps the moon will be our home in the future.

B: But man can’t live there because there is no air and no water. No life can live there. __65__

A: In that case, man can’t live there before solving these problems.

B．How can we?

C．There will be more and more people.

D．But I don’t think so.

E.How to solve the problem?

F.Pardon?

G.Of course I can see the moon and stars.

Can we live there?

 

查看答案和解析>>

科目：高中英語 來源：上海市2009-2010學(xué)年高二5月月考英語試題 題型：選詞填空

 

Section B

   Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need

 

A. agree          B. suffer        C. system       D. notice        AB. through  

AC. dangerous     AD. space       BC. limited     BD. absorbs      CD. let out

 

   For years scientist have been worried about the effects of air pollution on the earth’s natural conditions. Some believe the air inside many houses may be more    41    than the air outside. It may be one hundred times worse.

   Indoor air pollution can cause a person to feel tired, to    42     eye-pain, headache and other problems. Some pollutants can cause breathing disorders, diseases of blood and even cancer. Most scientists    43    that every modern house has some kind of indoor pollution. People began to    44    the problem in the early 1970s, when it was that builders began making houses and offices which did not waste energy. To do this they built buildings that    45    the flow of air between inside and outside. They also began using man-made building materials. These materials are now known to    46    harmful gases. As the problem became more serious, scientists began searching for a way to deal with it. They discovered a natural pollution control    47    for building green plants. Scientist do not really know how plants control air pollution. They believe that a plant’s leaves take in the pollutants. In exchange the plant produces oxygen    48    its leaves and through its tiny organizations on its roots. Scientists suggest that all buildings should have one large plant or several small plants inside for every nine square meters of space. Studies of different plants show that each    49    different chemicals. So the most effective way to clean the air is to use different kinds of plants. Having green plants inside your house can make it a prettier and healthier place.

 

查看答案和解析>>

同步練習(xí)冊答案