| The geology of the Earth’s surface is
dominated by the particular properties of water. Present on Earth in solid,
liquid, and gaseous states, water is exceptionally reactive. It dissolves,
transports, and precipitates many chemical compounds and is constantly modifying
the face of the Earth. Evaporated from the oceans, water vapor forms clouds, some of which are transported by wind over the continents. Condensation from the clouds provides the essential agent of continental erosion: rain. Precipitated onto the ground, the water trickles down to form brooks, streams, and rivers, constituting what is called the hydrographic network. This immense polarized network channels the water toward a single receptacle: an ocean. Gravity dominates this entire step in the cycle because water tends to minimize its potential energy by running from high altitudes towar A. precipitating onto the ground B. changing from a solid to a liquid state C. evaporating from the oceans D. being carried by wind [填空题]Earth’s surface releases some of the heat from the Sun as______.
[单项选择]It has been estimated that the earth's surface temperature has increased
______ one quarter to three quarters of a degree since 1850. ~ A. to B. by C. at D. with [单项选择]Without the sun's light ______ the earth's surface, no life could exist on the earth.
A. warms B. warmed C. warming D. to warm [单项选择]In Earth’s infancy, its surface was warm enough for life ____ the young Sun was fainter than it is today.
A. in spite of B. whether C. neither of which D. even though [单项选择]（ ） most of the earth's surface is covered by water, fresh water is very rare and precious.
A. As B. Once C. If D. Although [填空题]The average surface temperature of Earth keeps around 15℃.
[单项选择]All the useful energy at the surface of the earth comes from the activity of the sun. The sun heats and feeds creatures and mankind. Each year it provides men with two hundred million tons of grain and nearly ten million tons of wood, coal, oil, natural gas, and all other fuels are stored energy from the sun. (80) Some was collected by this season’ s plants as carbon compounds. Some was stored by plants and trees ages ago. Even waterpower derives from the sun. Water turned into vapor by the sun fails as rain. It courses down the mountains and is converted to electric power. Light transmits only the energy that comes from the sun’ s outer layer, and much of this energy that is directed towards the earth never arrives. About nine tenths of it is absorbed by the atmosphere of the earth. In fact, the earth itself gets only one half millionth of the sun’s entire output of radiant energy.
The sun is the source of all of the following EXCEPT______. A. gasoline B. natural gas C. atomic power D. animal fat [单项选择]It can be seen from the passage that the earth's supply of natural medicines
A. may never be exhausted. B. may be dropping rapidly. C. is surprisingly big. D. is as rich-as ever. [单项选择]第二篇A Very Slow Ride
The surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.
The earth has an outer shell of rigid pieces called tectonic plates (地壳构造板块).The plates include both ocean floor and dry land.Some have whole continents on top of them.The continents on top of the plates are just going along for a slow ride,moving only about four inches per year.But even this small movement causes three types of big interactions.
One type is ocean ridges.These ridges develop in places where two plates are moving away from each other.As the plates separate,hot magma(岩浆)flows up to fill the space.New crust(地壳)builds up on the plate boundaries and causes ocean ridges.These ridges form long mountain ranges,which only rise above the ocean surface in a few places.
Another type of reaction-trenches-occurs between two plates that are moving toward each other.As the plates meet,one bends downward
A. always changing. B. becoming smaller. C. moving faster. D. getting hotter. 我来回答: 提交
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