The key word in Paragraph 4 is ______.A.barriersB.ignoranceC.disabilityD.prejudice
The key word in Paragraph 4 is ______.
A.barriers
B.ignorance
C.disability
D.prejudice
The key word in Paragraph 4 is ______.
A.barriers
B.ignorance
C.disability
D.prejudice
第1题
Albert Einstein was the first to suggest the existence of stimulated emission in a paper published in 1917. However, for many years physicists thought that atoms and molecules always were much more likely to emit light spontaneously and that stimulated emission thus al- ways would be much weaker. It was not until after the Second World War that physicists began trying to make stimulated emission dominate. They sought ways by which one atom or molecule could stimulate many others to emit light, amplifying it to much higher powers.
The first to succeed was Charles H. Townes, then at Columbia University in New York. Instead of working with light, however, he worked with microwaves, which have a much longer wavelength, and built a device he called a "maser" for Microwave Amplification by the Stimulated Emission of Radiation. Although he thought of the key idea in 1951, the first maser was not completed until a couple of years. Before long, many other physicists were building masers and trying to discover how to produce stimulated emission at even shorter wavelengths.
The key concepts emerged about 1957. Townes and Artyur Schawlow, then at Bell Telephone Laboratories, wrote a long paper outlining the conditions needed to amplify stimulated emission of visible light waves. At about the same time, similar ideas crystallized in the mind of Gordon Gould, then a 37-year-old graduate student at Columbia, who wrote them down in a series of notebooks. Townes and Schawlow published their ideas in a scientific journal, Physical Review Letter, but Gould filed a patent application. Three decades later, people still argue about who deserves the credit For the concept of the laser.
The word "it" (line 5, para 1) refers to______.
A.light bulb
B.energy
C.molecule
D.atom
第2题
The word" radical" (Para 3 ) is closest in meaning to ______.
A.equal
B.extreme
C.excellent
D.basic
第3题
In the last Para, the word "unsavoury" probably means_____.
A.not easy to eat
B.disgusting
C.ugly
D.shameful
第5题
The word "obsession" (Para 3)in this passage means ______.
A.disturbance
B.preoccupation
C.compulsion
D.passion
第6题
What does the word "prototype" (Para 4) mean?
A.model
B.stereotype
C.example
D.figure
第7题
In Para 3, the word "exacerbated" is most similar in meaning to"______".
A.caused
B.encouraged
C.forced to continue
D.aggravated
第8题
The word" incessantly" (Para 1 ) could best be replaced by ______.
A.confidently
B.constantly
C.intelligently
D.optimistically
第9题
Which of the following best defines the word "distort" in Para 7?
A.Twist.
B.Interpret.
C.Ignore.
D.Judge.
第10题
A.response
B.plainness
C.excuse
D.dislike