日本成人片在线_久久免费精品视频_国产午夜精品久久久久久免费视_校花撩起jk露出白色内裤国产精品_av影片免费在线观看_国产小视频在线看_最新av免费在线观看_99久久99久久精品国产片_欧美成人猛片aaaaaaa_蜜桃免费网站一区二区三区

精英家教網 > 高中英語 > 題目詳情

Scientists say it may be five or six years _____ it is possible to test this medicine on human patients.

A. since                   B. after                   C. before     D. when

 

【答案】

C

【解析】

試題分析:句意:科學家說可能過武或六年才有可能把這種藥在病人身上試驗。since 自從;  after  在......之后;before  在......之前;  when 當......時候;It is /will be +時間段+before+(一般現在時的)句子“過多久才......”故選C。

考點:考查狀語從句的用法。

 

練習冊系列答案
相關習題

科目:高中英語 來源: 題型:閱讀理解

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

“To provide enough power, we need certain methods with high energy density(密度)”,said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries.”

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanical systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

His new idea is not only in the battery’s size, but also in its semiconductor(半導體). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.

“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶體結構) of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

Which of the following is true of Jae Kwon?

A. He teaches chemistry at MU.

B. He developed a chemical battery.

C. He is working on a nuclear energy source.

D. He made a breakthrough in computer engineering.

Jae Kwon gave examples in Paragraph 4_________.

A. to show chemical batteries are widely applied.

B. to introduce nuclear batteries can be safely used.

C. to describe a nuclear-powered system.

D. to introduce various energy sources.

Liquid semiconductor is used to _________.

A. get rid of the radioactive waste

B. test the power of nuclear batteries.

C. decrease the size of nuclear batteries

D. reduce the damage to lattice structure.

According to Jae Kwon, his nuclear battery _______.

A. uses a solid semiconductor

B. will soon replace the present ones.

C. could be extremely thin

D. has passed the final test.

The text is most probably a ________.

A. science news report  B. book review

C. newspaper ad    D. science fiction story

PART FOUR   WRITING (45%)

查看答案和解析>>

科目:高中英語 來源: 題型:

The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

A. what          B. which         C. that       D. though

查看答案和解析>>

科目:高中英語 來源: 題型:閱讀理解

    People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.

The research team have discovered that subordinate fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding(繁殖) rights within the group," explains Marian Wrong. “All other group members are nonbreeding females, each being 5-10% smaller than its next largest competitor. We wanted to find out how they maintain this precise size separation."

The reason for the size difference was easy to see. Once a subordinate fish grows to within 5-10% of the size of its larger competitor, it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.

It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily, by restraining how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise, the gobies simply refused the extra food they were offered, clearly preferring to remain small and avoid fights, over having a feast.

 The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.

While the habits of gobies may seem a little mysterious. Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical(等級的) societies remain stable.

The research has proved the fact that voluntary dieting is a habit far from exclusive to human.”As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature," the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long-term health and males regularly prefer females that are fatter than the females' own ideal."

65 When a goby grows to within 5-10% of the size of its larger competitor, it ______.

A. faces danger       B. has breeding rights

C. eats its competitor     D. leaves the group itself

66. The underlined words “the evicted fish" in Paragraph 3 refer to _____.

A. the fish beaten up       B. the fish found out

C. the fish fattened up     D. the fish driven away

67 The experiment showed that smaller fish ____.

A. fought over a feast        B. went on diet willingly

C. preferred some extra food  D. challenged the boss fish

68. What is the text mainly about?

A. Fish dieting and human dieting.

B. Dieting and health.

C. Human dieting.

D. Fish dieting. 

查看答案和解析>>

科目:高中英語 來源: 題型:閱讀理解

What makes a person a scientist? Does he have ways or tools of learning that are different from those of others??The answer is“no”.It isn't the tools a scientist uses but how he uses these tools which makes him a scientist .You will probably agree that knowing how to use a power is important to a carpenter(木匠).You will probably agree,too, that knowing how to investigate(調查),how to discover information ,is important to everyone. The scientist ,however ,goes one step further ;he must be sure that he has a reasonable answer to his questions and that his answer he gets to many questions is into a large set of ideas about how the world works.?

The scientist's knowledge must be exact .There's no room for half right or right just half the time. He must be as nearly right as the conditions permit .What works under one set of conditions at one time must work under the same conditions at other times. If the conditions are different ,any changes the scientist observes in a demonstration(實證)must be explained by the changes in the conditions. This is one reason why investigations are important in science .Albert Einstein ,who developed the Theory of Relativity ,arrived at this theory through mathematics. The accuracy(正確性)of his mathematics was later tested through investigation. Einstein's ideas were proved to be correct .A scientist uses many tools for measurements .Then the measurements are used to make mathematical calculations(計算)that may test his investigations.

1.What makes a scientist according to the passage??

A.The tools he uses.

B.His ways of learning.?

C.The way he uses his tools.

D.The various tools he uses.?

2.“...knowing how to investigate ,how to discover information ,is important to everyone.”The writer says this to show_______.?

A.the importance of information

B.the difference between scientists and ordinary people?

C.the importance of thinking

D.the difference between carpenters and ordinary people?

3.A sound scientific theory should be one that_______.?

A.works under one set of conditions at one time and also works under the same conditions at other times?

B.leaves no room for improvement?

C.doesn't allow any change even under different conditions?

D.can be used for many purposes?

4.What is the main idea of the passage??

A.Scientists are different from ordinary people.?

B.The Theory of Relativity.?

C.Exactness is the core(核心)of science.?

D.Exactness and way of using tools are the keys to making of a scientist.?

 

查看答案和解析>>

科目:高中英語 來源:2012-2013學年河北省邢臺一中高二第三次月考英語試卷(帶解析) 題型:單選題

Nowadays,scientists are working hard to find a best way of treating addictions ________ drugs.

A.ofB.inC.onD.to

查看答案和解析>>

同步練習冊答案
国产污污视频在线观看| 日本不卡一区二区| 久草在线综合| 成人在线高清| 在线一区av| 欧美另类tv| 天堂аⅴ在线地址8| 新版中文字幕在线资源| 人成网站在线观看| 国产福利第一视频| 国产又色又爽又黄又免费| 天干夜夜爽爽日日日日| 圆产精品久久久久久久久久久 | 免费亚洲电影| 毛片电影在线| 国产传媒在线观看| 1234区中文字幕在线观看| 99热国产在线| 自拍亚洲图区| 免费av不卡在线观看| 亚洲h片在线看| 四季久久免费一区二区三区四区| www免费视频观看在线| 亚洲免费视频一区二区三区| av电影在线观看| av中文字幕在线| 日本在线免费| 尤物视频在线看| 国产蜜臀在线| 欧美magnet| 91成人在线观看喷潮教学| 久久综合九色综合97婷婷女人| 视频一区中文字幕国产| 久久久噜噜噜| 国产综合色在线| 成人黄色小视频在线观看| 99久久亚洲一区二区三区青草| 91亚洲精品久久久蜜桃| 国产日韩欧美在线一区| 亚洲视频香蕉人妖| 亚洲成a人片在线不卡一二三区| 亚洲高清免费在线| 在线观看日韩国产| 欧美草草影院在线视频| 亚洲美女av在线播放| 神马国产精品影院av| 美日韩精品免费视频| 国内精品400部情侣激情| 欧美一级淫片播放口| 国产欧美一区二区白浆黑人| 国产精品乱子乱xxxx| 日本一区二区三区免费观看| 国产欧美123| 男人操女人免费| 99国产精品免费视频| 精品人妻一区二区三区四区| 麻豆91精品91久久久| 久久久精品毛片| 亚洲成人黄色片| 免费一级在线观看播放网址| 色呦呦呦在线观看| 欧美久久久网站| 日韩av三区| 亚洲一本视频| 国产一区二区不卡| 亚洲国产成人一区二区三区| 欧美日韩国产中文精品字幕自在自线| 欧美一区二区在线不卡| 中文字幕日韩在线播放| 国产99在线|中文| 久久久久无码国产精品一区| 亚洲色欲久久久综合网东京热| 波多野结衣xxxx| 极品人妻videosss人妻| 综合激情网五月| 天天色天天操天天射| 免费不卡视频| 国产精久久久| 国产一区二区三区自拍| 国产精品一区二区91| 亚洲私人黄色宅男| 欧美一级日韩不卡播放免费| 日韩亚洲在线观看| 国产在线拍揄自揄视频不卡99| 神马一区二区影院| jizz大全欧美jizzcom| 国产一区二区三区四区在线| 亚洲精品国产欧美在线观看| 天堂av在线7| 一区二区电影免费观看| 欧洲毛片在线视频免费观看| 日产国产欧美视频一区精品| 中文字幕欧美激情| 69堂成人精品免费视频| 欧美日韩成人网| 精品蜜桃一区二区三区| 日韩欧美黄色大片| 一二三四国产精品| 国产99视频在线| 新版中文在线官网| 五月天亚洲一区| 另类人妖一区二区av| 亚洲欧美日韩一区二区| 亚洲黄色av网站| 国产精品露脸自拍| 干日本少妇视频| 波多野结衣av在线免费观看| 中文字幕日韩国产| 久草中文在线| 亚洲精品国产动漫| 国产一区视频网站| 色婷婷激情综合| 九九热r在线视频精品| 久久精品午夜一区二区福利| 777视频在线| 国语对白一区二区| 理论在线观看| 久久动漫网址| 国产麻豆午夜三级精品| 91福利在线播放| 欧美激情成人在线视频| 亚洲一区二区精品在线| 日韩Av无码精品| 国产乱淫a∨片免费观看| 牛牛精品在线视频| 婷婷综合激情| 中文字幕乱码日本亚洲一区二区| 亚洲成人中文字幕| 成人福利视频网| 亚洲色图久久久| 特级毛片www| 主播国产精品| 亚洲精品国产成人影院| 国产精品视频一二三| 国产视频久久久| 国产精品 日韩| 国产精品嫩草69影院| 亚洲在线免费观看视频| 中文字幕色婷婷在线视频| 亚洲网站在线| 一区二区三区波多野结衣在线观看| 中文字幕国产精品| 一级日韩一区在线观看| 国产精品久久免费观看| 三级在线电影| 九九热爱视频精品视频| 久久久久久久久久久久久女国产乱| 日韩av在线一区二区| 国产青春久久久国产毛片| 国产伦理在线观看| 亚洲经典一区二区三区| 欧美不卡在线观看| 国产成人在线电影| 精品sm在线观看| 久久精品99| 男人天堂av电影| 日韩毛片在线一区二区毛片| 伊人成综合网伊人222| 久久久久青草大香线综合精品| 亚洲欧美三级伦理| 四虎永久国产精品| 神马久久精品综合| 麻豆网站在线看| 在线日本成人| 欧美在线不卡视频| 成人午夜激情免费视频| 亚洲欧美日韩偷拍| 日本午夜在线视频| 国产精品二区不卡| 亚洲成国产人片在线观看| 欧美综合第一页| 91精品视频国产| av超碰在线观看| 精品理论电影| 亚洲国产一区二区视频| 国产精品高潮呻吟久久av无限| 在线观看免费不卡av| 乱精品一区字幕二区| 久久99国产精品久久99大师 | a黄色片在线观看| 亚洲欧洲综合| 欧美日韩精品免费观看视频| 国产精品国产亚洲精品看不卡15| 三上悠亚影音先锋| 色影院视频在线| 一区二区三区精品视频在线观看 | 色婷婷激情视频| 香蕉视频在线网站| 久久久久久美女精品 | 国产成人黄色| 无吗不卡中文字幕| 91视频免费在线| 2019男人天堂| 国产精品xx| 国产白丝网站精品污在线入口| 尤物九九久久国产精品的特点 | 91精品综合| 欧美在线啊v一区| 日本在线播放一区| 午夜婷婷在线观看| 国产一区二区三区视频在线| 国产日产欧美精品一区二区三区| 5566成人精品视频免费| 国产精品无码自拍| аⅴ资源新版在线天堂| 六月天综合网| 国产一区二区日韩| 国产自偷自偷免费一区 | 99在线精品观看| 孩xxxx性bbbb欧美| 一级黄色免费视频| 免费a级毛片在线播放| 日本不卡不码高清免费观看| 亚洲欧美色图片| 牛夜精品久久久久久久| 日本v片在线免费观看| 香蕉国产精品偷在线观看不卡| 亚洲经典中文字幕| 欧美日韩成人免费视频| 亚洲 国产 欧美 日韩| 黄色亚洲精品| 国产丝袜一区二区三区免费视频| 欧美变态另类刺激| 在线视频色在线| 日韩专区中文字幕一区二区| 最近中文字幕2019免费| 久热精品在线播放| 成人动漫在线播放| 国产一区欧美二区| 高清欧美一区二区三区| 国产美女免费网站| av成人亚洲| 一区av在线播放| 欧美1o一11sex性hdhd| 亚洲中文字幕一区二区| 天天做天天爱天天综合网2021| 日韩一区二区三区观看| 一女被多男玩喷潮视频| 欧洲毛片在线| 国产一级精品在线| 2018日韩中文字幕| 国产激情无码一区二区三区| 亚洲人成网站在线在线观看| 精品久久香蕉国产线看观看亚洲 | 久久久久久久国产精品毛片| 亚洲精品黑牛一区二区三区| 欧美亚洲综合色| 欧美一级视频在线播放| 日韩av视屏| 国产suv精品一区二区三区| 欧美壮男野外gaytube| 黄色一级片中国| 日韩伦理一区二区三区| 6080日韩午夜伦伦午夜伦| 免费毛片小视频| 日本黄色片在线观看| 91论坛在线播放| 国产高清精品一区二区| 一级特黄录像免费看| 午夜精品网站| 另类色图亚洲色图| a资源在线观看| 都市激情久久| 日韩欧美www| 特级黄色片视频| 亚洲最新无码中文字幕久久| 亚洲第一av色| 日韩国产一级片| 黄在线免费观看| 中文字幕乱码日本亚洲一区二区| 蜜桃成人在线| 国产无遮挡在线视频免费观看| 久久精品久久综合| 国产一区二区色| 亚洲最大成人在线视频| 国产毛片一区| 国产成人啪精品视频免费网| 日本天堂网在线| 亚洲乱码视频| 国产91精品视频在线观看| 日韩三级免费看| 亚洲国产一区二区三区a毛片 | 国产成a人亚洲| 成人在线国产精品| 国产又粗又猛又黄| 免费人成在线不卡| 91麻豆国产语对白在线观看| av手机免费看| 国产在线视频精品一区| av一区二区三区四区电影| 国产夫绿帽单男3p精品视频| 极品少妇一区二区| 国产精品视频一区二区三区经| 开心激情综合网| av网站免费线看精品| 国产精品一级久久久| 色屁屁草草影院ccyycom| 成人av网址在线| 日韩资源av在线| 黄色av网站在线看| 亚洲欧美日韩在线| www黄色日本| 蜜桃成人精品| 精品久久久三级丝袜| 加勒比综合在线| 久久国产精品亚洲人一区二区三区| 美女视频久久黄| 亚洲 欧美 中文字幕| 肉丝袜脚交视频一区二区| 成人网在线视频| 香蕉视频在线网站| 国产精品欧美综合在线| 日本人体一区二区| 国产精品专区免费| 精品美女一区二区| 亚洲精品自拍视频在线观看| 欧美韩国一区| 国产成人精品免费视频| 一级黄色录像在线观看| 亚洲欧美日韩国产yyy| 朝桐光av在线一区二区三区| 成人av一区二区三区| 中文字幕日韩精品一区二区| 欧美78videosex性欧美| 欧美久久久久中文字幕| 欧美 日本 国产| 欧美成人激情| 国产精品高潮呻吟久久av无限| 人妻va精品va欧美va| 国产欧美精品日韩区二区麻豆天美| www.日本在线播放| 亚洲电影二区| 日韩在线资源网| 日韩av免费播放| 不卡大黄网站免费看| 欧美一级中文字幕| 亚洲电影有码| 一区二区三区四区在线观看视频| 男人的天堂一区二区| 国产一二精品视频| 国产又粗又爽又黄的视频| 毛片无码国产| 一区二区三区视频观看| 嫩草影院一区二区三区| a级精品国产片在线观看| 国产黄色片免费在线观看| 亚洲综合视频| 美日韩丰满少妇在线观看| 国产又粗又猛又爽又黄91| 久久综合九色综合欧美98| 国产 福利 在线| 农村少妇一区二区三区四区五区 | 国产精品久久久久久超碰| 在线免费日韩| 色94色欧美sute亚洲线路一久 | 国产又大又黄又粗又爽| 欧美日韩国产一区二区三区不卡| 欧美诱惑福利视频| 亚洲精品97久久久babes| 色88888久久久久久影院野外| 加勒比一区二区| 美女爽到呻吟久久久久| 五月天色一区| 久久不卡日韩美女| 九九热精品视频| 粉嫩欧美一区二区三区| 色综合久久久网| www色aa色aawww| 成人精品国产免费网站| 1024av视频| 少妇一区二区视频| 91在线视频九色| 丁香高清在线观看完整电影视频| 精品视频在线播放| 国产精品无码白浆高潮| 亚洲免费色视频| 久久午夜福利电影| 精品一区二区影视| 六月丁香激情网| 欧美久久综合网| 国产精品一码二码三码在线| 日韩欧美精品一区二区三区| 俺去啦;欧美日韩| 91成人福利在线观看| 欧美在线影院一区二区| 欧美成人一二三区| 久久久国产精华| 娇妻高潮浓精白浆xxⅹ| 久久精品动漫| 777777av| 五月天综合网站| 神马影院我不卡午夜| 中文字幕一区日韩精品| 国产欧美日韩亚洲精品| 91jq激情在线观看| 欧美国产日韩二区| www亚洲人| 国产亚洲欧美视频| 黄页视频在线免费观看| 4438成人网|