更多"[单选题]The author of this essay seems"的相关试题:
[单选题]Ecological vehicles are made of materials that can be easily ( )once they are dumped.
A.realistic
B.racial
C.recycled
D.rebellious
[单选题]The chairperson of Walter Bros. announced that this year's annual bonuses will be ( ) to company
employees on Friday.
A. awarded
B. transacted
A.
B.published
C.
D.discarded
[单选题]Golf Weekly is a newly published magazine that caters_________ to experienced and inexperienced golfers who are just learning to play the game.
A.Both
B.neither
C.either
D.so
[单选题]We explicitly make allowance for the fact that production
.______when the artist dies, implying that the collectors can be sure that in the future no new similar pieces of art will put pressure on the prices in this specific market segment.
A.confines
B.conforms
C.ceases
D.continues
[单选题]Her new boyfriend has omitted to tell her that he had married once.
A.forgotten
B.failed
C.deleted
D.left out
[单选题]The girl has awakened the feelings in him that his thought had been__________long ago.
A.called up
B.taken up
C.stamped out
D.handed in
[单选题]We have to change the public's perception that money is everything.
A.sight
B.belief
C.interest
D.pressure
[不定项选择题]共用题干
Black Holes
Most scientists agree that black holes exist but are nearly impossible to locate.A black hole
in the universe is not a solid object, like a planet, but it is shaped like a sphere(球体).
Astronomers(天文学家)think that at the center of a black hole there is a single point in space
with infinite(无限的)density(稠密).This single point is called a singularity(奇点).If the
singularity theory is correct,it means that when a massive star collapses,all the material in it
disappears into the singularity.The center of a black hole would not really be a hole at all,but
an infinitely dense point.Anything that crosses the black hole is pulled in by its great gravity.
Although black holes do exist,they are difficult to observe.These are the reasons.
No light or anything else comes out of black holes.As a result,they are invisible to a telescope.
In astronomical terms,black holes are truly tiny.For example,a black hole formed by the collapse of a giant star would have an event horizon(视界)only 18 miles across.
The nearest black holes would be dozens of light years away from Earth.One light
year is about 6 trillion(万亿)miles. Even the most powerful telescopes could not pick out
an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are
still answers to be found,however,so black holes remain one of the mysteries of the universe.
The Hubble Space Telescope helps scientists to understand the nature of the universe.
A.Right
B.Wrong
C.Not mentioned