单词：quadrivalents
[医] 四价的
a. Having a valence of four; capable of combining with,
being replaced by, or compared with, four monad atoms; tetravalent; --
said of certain atoms and radicals; thus, carbon and silicon are
quadrivalent elements.
单词：quadrivalents 相关文章
New Heart Stents Better Than Old Ones, Study Says A heart stent is a mesh tube made of metal that, when inserted into an artery, keeps it open. Stents can be metal only or they can contain medicine released once the stent is in place. These are calle
VOA标准英语2012年(九月)
A: I want to open an account. B: What kind of account do you want to open? A: I want to open a checking account. B: Do you know the minimum balance youre required to keep? A: How much is that? B: You have to maintain a minimum balance of $100. A: Rea
英语情景对话-银行
A: I need to open an account. B: Do you know what kind you want to open? A: I want a checking account. B: Do you know what the minimum balance is? A: What is that? B: You need to keep it at $100. A: Thats it? B: Thats the least amount you can have. A
英语情景对话-银行
A: I would like to open an account today. B: What kind? A: I want to open a checking account. B: You need to keep a minimum balance. A: How much is it? B: You need at least $100 in your account. A: Is that all? B: Yes. Thats the minimum. A: What happ
英语情景对话-银行
Good morning. Oh, what a day. What a lovely day. Its a pleasure to be addressing the Wake Forest graduating Class of 2015. I want to start by thanking the administration and the Trustees for inviting me to speak. I want to thank them for giving me an
英语语言学习
This is the VOA Special English Health Report. A coronary stent is a small tube that is used to treat heart patients. The tube is made of A stent is a tube of wire mesh wire mesh. Doctors place it inside an artery that has narrowed. They expand the
VOA慢速英语2007年（六）月
This is the VOA Special English Health Report. Today we have the second half of a report about some concerns with the use of drug- treated coronary stents. These are small metal tubes designed to be placed inside arteries in heart patients. The sten
VOA慢速英语2007年（六）月
New Drug Makes Surgery Safer For Patients With Stents Heart stents open blocked arteries and restore blood flow. They can also help support weak arteries and keep them open. Stents are implanted during a common procedure called angioplasty. During th
VOA标准英语2012年(一月)
If you heard the first part, youll know that Princess Talia has woken up somewhat confused. She is a student at an ancient college, but shes not quite sure how she got there. In this episode we will find out how she fits into her new surroundings. Ou
Children’s Stories-儿童故事集
Advertisements 广告 SHANGHAI TOYS IMPORT AND EXPORT CORPORATION 上海玩具进出口公司广告 Shanghai Toys Imp. Exp. Corp, the first combination of industry and trade in China approved by the State Council of the People's Republic of China, is
实用英语
President Faust, Board of Overseers, faculty, friends, alumni, proud parents, 浮士德校长、校监委员会成员们、老师、朋友、校友、自豪的家长们、 members of the ad board, and graduates of the greatest university in the world
公众人物毕业演讲
By Carol Pearson Washington, DC 08 November 2006 watch Heart Stent report Heart stents are lifesaving medical devices that help prevent heart attacks. Most of these stents are coated with various drugs, but mounting data suggest drug-coated stents c
2006年VOA标准英语（十一月)
Rival Palestinian factions have clashed in the Gaza Strip, which is ruled by the Islamic militant group Hamas. At least four people, including two Hamas policemen, have been killed and dozens wounded. Robert Berger reports from the VOA bureau in Jer
VOA标准英语2008年（八月）
BEIJING, April 9 (Xinhuanet) -- The annual Franco-Chinese Croisements 2011 cultural festival(节日) kicked off in Beijing's Sanlitun Village Thursday night, accompanying an opening ceremony for the 8th Annual French Cinema Panorama. Sylvie Bermann (
英语新闻
今天我们要学的词是rival。 Rival, 是对头的意思。 President-elect Obama named his one-time chief Democratic rival Senator Hillary Clinton as Secretary of State, 美国当选总统奥巴马提名自己原来的民主党对手，联邦参议
英语每日一词
达喀尔首次驶入玻利维亚 LA PAZ, Jan. 12 (Xinhua) -- Bolivian President Evo Morales Sunday celebrated his country's inclusion in the Dakar Rally, saying it marks the first time ever Bolivia has hosted a world-class sporting event. The race e
英语新闻
A flying robot piloted by brainwaves is just one of the ingenious new devices coming out of a top US university. Students are showing off their latest creations at the Maryland Robotics Day including the Neuro Sky Mindset and a snake-inspired search-
世界各地新闻集锦
The Norwegian sailor, Jarle Andhoy with three other men, sailed to the Antarctic illegally. One of the men is a New Zealander. They did not have permission from the Norwegian government or from New Zealand. They wanted to know what happened to the bo
新西兰英语
Harpsichord The harpsichord was the most popular of the early keyboard instruments. The strings were made of metal and plucked with quills. The metallic sound was not pleasing to musicians ears, but Mozart figured out a way to make music sound more b
名人认知系列 Who Was