The moon’s surface gravity is only about____as strong as the earth’s surface gravity.
A.one-six
B.one-sixth
C.six-one
D.one-sixst
A.one-six
B.one-sixth
C.six-one
D.one-sixst
第1题
A. the star moved away from the sun
B. another star happened to come near the sun
C. fhe sun and the moon raised the tides on the earth
D. a large tidal wave of a star travelled over the surface of the sun
第2题
Text 2 To understand how astrology works, we should first take a quick look at the sky. Although the stars are at enormous distances, they do indeed give the impression of being affixed to the inner surface of a great hollow sphere surrounding the earth. Ancient people, in fact, literally believed in the existence of such a celestial sphere. As the earth spins on its axis, the celestial sphere appears to turn about us each day, pivoting at points on a line with the earth's axis of rotation. This daily turning of the sphere carries the stars around the sky, causing most of them to rise and set, but they, and constellations they define, maintains fixed patterns on the sphere, just as the continent of Australian maintains its shape on a spinning globe of the earth. Thus the stars were called fixed stars.
The motion of the sun along the ecliptic is, of course, merely a reflection of the revolution of the earth around the sun, but the ancients believed the earth was fixed and the sun had an independent motion of its own, eastward among the stars. The glare of sunlight hides the stars in daytime, but the ancients were aware that the stars were up there even at night, and the slow eastward motion of the sun around the sky, at the rate of about thirty degrees each month, caused different stars to be visible at night at different times of the year.
The moon, revolving around the earth each month, also has an independent motion in the sky. The moon, however, changes its position relatively rapidly. Although it appears to rise and set each day, as does nearly everything else in the sky, we can see the moon changing position during as short an interval as an hour or so. The moon's path around the earth lies nearly in the same plane as the earth's path around the sun, so the moon is never seen very far from the ecliptic in the sky. There are five other objects visible to the naked eye that also appear to move in respect to the fixed background of stars on the celestial sphere. These are the planets Mercury, Venus, Mars, Jupiter, and the Saturn. All of them revolve around the sun in nearly the same plane as the earth does, so they, like the moon, always appear near the ecliptic. Because we see the planets from the moving earth, however, they behave in a complicated way, with their apparent motions on the celestial sphere reflection both their own independent motions around the sun and our motion as well.
第26题:The ancient people believed that ________.
[A] the earth was spinning on the axis of the sky
[B] the sky was a hollow sphere spinning around the earth
[C] the patterns of stars on the sky would never change
[D] the stars around the sky were not stationary
第3题
【C1】
A.destroyed
B.stained
C.changed
D.consolidated
第4题
We believe, however, that some two thousand million years ago, another star wandering through space, happened to come near our sun. Just as the sun and the moon raise tides on the earth, so this star must have raised tides on the surface of the sun. But they were very different from the small tides that are raised in our oceans; a large tidal wave' must have travelled over the surface of the sun, at last forming a mountain so high that we cannot imagine it. As the cause of the disturbance (动荡) came nearer, so the mountain rose higher and higher. And before the star began to move away again, its tidal pull had become so powerful that this mountain was torn to pieces and threw off small parts of itself into space. These small pieces have been going round the sun ever since. They are the planets (行星).
Millions of stars are______.
A.following a regular path in space
B.always travelling together
C.seldom wandering about in the universe
D.moving about without a fixed course
第5题
Which of the following is true about the motion of the moon?
[A] The moon and the sun are moving in the same plane.
[B] The moon revolved along the ecliptic.
[C] The moon moves faster than the sun.
[D] The position of the moon can be found changed in an hour's time.
第7题
Warming waters are known to (28)to coral bleaching(珊瑚白化) and they take up more space than cooler waters, raising sea (29). While the top of the ocean is studied, its depths are more difficult to (30)The researchers gathered 150 years of ocean temperature data in order to get better (31)of heat absorption from surface to seabed. They gathered together temperature readings collected by everything from a 19th century (32)of British naval ships to modern automated ocean probes. The extensive data sources, (33)with computer simulations(计算机模拟), created a timeline of ocean temperature changes, including cooling from volcanic outbreaks and warming from fossil fuel (34).
About 35 percent of the heat taken in by the oceans during the industrial era now residents at a (35)of more than 700 meters, the researchers found. They say they&39;re unsure(36)whether the deep-sea warming canceled out warming at the sea&39;s surface.
A absorb
B combined
C contribute
D depth
E emission
F.explore
G explore
H.floor
I.heights
J.indifferent
K level
L.mixed
M picture
N unsure
O voyage
第8题
If the current and wind are in opposite directions,the sea surface represents ______.
A.a greatly reduced wind speed
B.a higher wind speed than what really exists
C.a lower wind speed than what really exists
D.more turbulent winds
第9题
Which factor(s) might indicate that a towline should be removed from service?
A.Visible damage to the towline,including fishhooks
B.Measurements showing a decrease in diameter
C.A surface condition of corrosion and discoloration
D.All of the above
第10题
A.most painful B.most regretful C.clearest D.earliest E.youngest