No one knows exactly ______ this important discovery was made.
A. that B. that how C. what D. when
高一英语单项填空简单题
No one knows exactly ______ this important discovery was made.
A. that B. that how C. what D. when
高一英语单项填空简单题查看答案及解析
There is no way of knowing why one man makes an important discovery ______ another man, also intelligent, fails.
A. since B. if C. as D. while
高一英语单项填空简单题查看答案及解析
There’s no way of knowing why one man makes an important discovery ________ another man, also intelligent, fails.
A.since B.if C.as D.while
高一英语单项填空困难题查看答案及解析
Almost every machine with moving parts has wheels, yet no one knows exactly when the first wheel was invented or what it was used for. We do know, however, that they existed over 5,500 years ago in ancient Asia.
The oldest known transport wheel was discovered in 2002 in Slovenia. It is over 5,100 years old. Evidence suggests that wheels for transport didn't become popular for a while, though. This could be because animals did a perfectly good job of carrying farming tools and humans around.
But it could also be because of a difficult situation. While wheels need to roll on smooth surfaces(光滑表面), roads with smooth surfaces weren't going to be built until there was plenty of demand for them. Finally, road surfaces did become smoother, but this difficult situation appeared again a few centuries later. There had been no important changes in wheel and vehicle design before the arrival of moden road design.
In the mid-1700s, a Frenchman came up with a new design of road—a base layer (层) of large stones covered with a thin layer of smaller stones. A Scotsman improved on this design in the 1820s and a strong, lasting road surface became a reality. At around the same lime, metal hubs (the central part of a wheel) came into being, followed by the pneumatic tyre(充气轮胎) in 1846. Alloy(合金) wheels were invented in 1967, sixty years after the appearance of tarmacked roads (柏油路). As wheel design took off, vehicles got faster and faster.
1. What might explain why transport wheels didn't become popular for some time?
A. Few knew how to use transport wheels.
B. Humans carried farming tools just as well.
C. Animals were a good means of transport.
D. The existence(存在)of transport wheels was not known.
2.How is the last paragraph mainly developed?
A. By giving examples.
B. By making comparisons.
C. By giving discussion
D. By making classifications.(分类)
3.What is the passage mainly about?
A. The beginning of road design.
B. The development of transport wheels.
C. The history of public transport.
D. His invention of fast-moving vehicles.
高一英语阅读理解简单题查看答案及解析
No one really knows exactly of when the first people arrived in we now know as California
A.where B.when C. what D.which
高一英语单项填空中等难度题查看答案及解析
No one knows exactly 1. the earth began, as it happened so long ago. However, according to a 2.(wide) accepted theory, the universe began 3.a “Big Bang” that threw matter in all directions.
What it was to become was 4. (certain) until between 4.5 and 3.8 billion years ago 5. the dust settled into a solid globe. The earth became so violent 6. it was not clear whether the shape would last or no.
People are 7.(put) too much carbon dioxide into the atmosphere, which prevents heat from 8.(escape) from the earth into space. As a result of this, many scientists believe the earth may become too hot to live on. So9.life will continue on the earth for millions of years to come will depend on whether this problem can be10. (solve).
高一英语短文填空中等难度题查看答案及解析
No one knows exact 1. the earth began, as it happened so long ago. 2. , according to a 3. (wide) accepted theory, the universe began with a “Big Bang” that threw matter 4. all directions. After that, atoms began to form and combine to create stars and other bodies.
Water 5. (appear) on other planets like Mars but, unlike the earth, it had disappeared later. 6. was not immediately obvious that water was to be fundamental to the development of life. What many scientists believe is that the continued 7. (present) of water allowed the earth 8. (dissolve) harmful gases and acids into the oceans and seas. This produced 9. chain reaction, 10. made it possible for life to develop.
高一英语语法填空中等难度题查看答案及解析
. No one knows when exactly the lake _____.
A. took its place B. came into being C. happened D. came over
高一英语单项填空简单题查看答案及解析
阅读下面材料,在空白处填入适当的内容(1个单词)或括号内单词的正确形式。
No one knows 1. (exact) how the earth began, as it happened so long ago. However, according to a widely 2. (accept) theory, the universe began 3. a “Big Bang” that threw matter in all 4. (direction). For several billion years after the “Big Bang”, the earth was still just a cloud of dust. 5. it was to become was 6. (certain) until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe. The earth became so 7. (violence) that it was not clear 8. the shape would last or not. It exploded loudly with fire and rock. They were in time 9. (produce) carbon dioxide, nitrogen, water vapour and other gases, which were to make the earth’s atmosphere. What is even more important is that as the earth cooled down, water began to appear on 10. surface.
高一英语语法填空中等难度题查看答案及解析
DNA(Deoxyribonucleic acid)is one of the most important discoveries in science. DNA is the plan for the human being,as a blueprint is the plan for building. DNA makes a person look the way he does. A person’s DNA comes from a mixing of his parents’ DNA. That’s why a child looks like his parents. But,besides controlling things such as height and hair color,DNA can also give people diseases. Scientists are now studying DNA to cure(治疗) diseases.
In the seventies, scientists developed a process called recombinant (重新组合) or RDNA. Although it sounds difficult to understand,RDNA simply means taking DNA from one animal or plant and putting it into another. By doing so,scientists can create new beings. In doing so,scientists can better understand DNA, especially what parts of DNA do. After they understand DNA,scientists can begin to cure diseases. Often,the new being created itself will be the cure.
Besides curing diseases,RDNA research can also do other things. For example, scientists in Japan have already created “super-trees”. Trees help humans,because they take CO2, which poisons humans, from the air and turns it into oxygen, which lets humans breathe. “Super-trees” do this too,but do it much faster. As things such as cars and factories have already put much CO2 in the area,“super-trees” are badly needed.
Unfortunately,there is serious danger in RDNA research. Scientists want to create animals to cure old diseases,but these new animals may also create new diseases. It will be a serious problem if the animals escape from the science laboratory and into nature. As these animals are not natural, they may let loose many new powerful diseases.
As a result,RDNA research will create many solutions(解决方案),but it will also create many problems.
1.From the passage, we can know that a boy looks like his parents because .
A. he is son of his parents
B. his parents’ DNA decides his appearance
C. he has received DNA from his father or his mother
D. scientists have put some of his parents’ DNA into him
2.The following statements are true about RDNA research EXCEPT
A. RDNA research will benefit human beings a lot
B. super-trees might be widely planted around the world
C. scientists have not completely understood DNA
D. the research has been stopped because the created animals carry virus (病毒)
3.What does the underlined expression “let loose” in paragraph 4 probably mean?
A. let...go free B. get rid of (去除) C. absorb (吸收) D. survive
4.What is the best title for the passage?
A. The DNA Research in Japan
B. A New Way of DNA Research in Japan
C. The Advantages and Disadvantages of RDNA
D. The Causes and Effects of DNA Research
高一英语阅读理解中等难度题查看答案及解析