单词：primitive sperm cell
单词：primitive sperm cell 相关文章
By Caty Weaver Broadcast: July 25, 2003 This is Bill White with the VOA Special English Environment Report. Researchers say they have found a way to reduce the cost of some 1)fuel cell production. The
VOA2003（下）-环境与健康
RACHEL MARTIN, HOST: A wide-ranging study shows that sperm counts are plummeting throughout the Western world, and scientists don't know why. NPR health correspondent Rob Stein suggests some of the potential reasons. ROB STEIN, BYLINE: In Margaret At
2017年NPR美国国家公共电台7月
Why are there males and females? Why are there two sexes instead of three, or twelve, or one? On this Moment of Science we'll learn why two is the magic number. Let's start with why there is sex at all. When two organisms reproduce sexually, sperm an
英语听力广播—Listening
And they have the blemish both front and rear from a facet where the opposite tooth interlocked with it. 在牙齿前后的齿面都有缺陷就是与对面牙齿相交错的地方。 What happens is that the root is anchored well into the lower jaw.
侏罗纪搏击俱乐部
The sperm whale hits him dead in the centre of his body throwing the Megalodon's enormous weight in a tumble motion under the ocean. 抹香鲸结结实实地撞中它的身体中间，把巨齿鲨庞大的身躯撞得在海洋中翻滚。 The Megalod
侏罗纪搏击俱乐部
For something that could revolutionize the world, its come along very slowly. The fuel cell was invented in 1839, but there was little development until the 1950s when NASA started to use them in space where they are still used today. Now, after yea
国家地理2008年
What Is Progeria? Progeria was first described in the nineteenth century. The mysterious disease is often thought of as premature aging. Children with progeria are normal for their first year of life, but then develop medical problems normally seen i
英语听力文摘 English Digest
Egg Cells 卵细胞 Do you know what an egg cell is? 你知道什么是卵细胞吗？ An egg cell is necessary for reproduction. 卵细胞是繁殖的必要条件。 Animals have egg cells. 动物有卵细胞。 Then does every animal have egg cells
与美国小学生一起学英文第10册
Why are there males and females? Why are there two sexes instead of three, or twelve, or one? On todayss Moment of Science we'll learn why two is the magic number. Let's start with why there is sex at all. When two organisms reproduce sexually, sperm
英语听力文摘 English Digest
By Victoria Cavaliere New York 16 October 2007 An annual stem cell research conference in New York has been bringing together some of the field's top scientists to discuss breakthroughs in stem cell research and what proponents call its long-term app
2007年VOA常速英语（十月）
By Paul Sisco Washington 17 April 2008 Federal regulators in Washington have approved plans to upgrade the nation's Emergency Alert System to include text messages to cellphones and other mobile devices. VOA's Paul Sisco has more in this Searching fo
VOA常速英语2008年（四月）
Beijing, Sept. 6 (Xinhua) -- A sperm donation scandal disclosed recently has aroused growing concern in the United States. According to the New York Times' report, Ryan Kramer, the son of a donor, found that he has more than 150 half-siblings - they
英语新闻
WASHINGTON, Aug. 4 (Xinhua) -- Researchers have found a way to turn mouse embryonic stem cells into sperm and this finding opens up new avenues for infertility research and treatment, according to astudy published Thursday in the online edition of jo
英语新闻
Turn Off Your Cell Phone 关掉你的手机 We went to the movie the other night. I sat in an aisle seat as I usually do, because it feels a little roomier. Just as the feature was about to start, a blonde from the center of the row got up and starte
趣味英语
如果嫌要发短信的内容长，不方便交流，费时费力，你建议对方打电话，可以说Let's go primitive。primitive的意思是原始的，go primitive就是采用原始的方式，显然电话比短信出现的早，相比之下就
美国俚语
WASHINGTON, May 11 (Xinhua) -- Researchers at Brigham and Women 's Hospital (BWH), a teaching affiliate of Harvard Medical School, have identified(鉴定) a human lung stem cell that is self-renewing and capable of forming and integrating multiple bi
英语新闻
Our bodies are amazing. Although things go wrong at times, it's remarkable they work at all when one considers the complexities of their operation. Don and Ya?l present some awards to a few of the outstanding components. [APPLAUSE] D: Good evening, Y
英语时差8，16
What was actually interesting to us was not that the bacteria made light, but when the bacteria made light. 事实上，我们感兴趣的部分并不是细菌会不会发光，而是细菌何时发光。 What we noticed is when the bacteria were alo
TED演讲教育篇
In mammals, the sex of a baby is determined by the combination of chromosomes it inherits from its parents. Nearly every cell in a male body has two different sex chromosomesone is shaped like an X and one is shaped like a Y. Females also have two se
英语时差8，16