问题 选择题

在七大洲中,面积最小的大洲是:

A.欧洲

B.亚洲

C.北美洲

D.大洋洲

答案

D

题目分析:在七大洲中,面积最小的大洲是大洋洲,最大的是亚洲,欧洲全部位于北半球,北美洲位于西半球。

点评:本题还可以考查七大洲面积由大到小排序为亚非北南美,南极欧大洋;亚洲和欧洲是紧密在一块大陆,叫做亚欧大陆;各大洲的界线:①亚洲和欧洲的分界是乌拉尔山——乌拉尔河——里海——大高加索山——黑海——土耳其海峡——地中海;②亚洲与非洲的分界线是地中海——苏伊士运河——红海;③欧洲与非洲的分界线是直布罗陀海峡——地中海;④亚洲与北美洲的分界是白令海峡;⑤北美洲与南美洲的分界是巴拿马运河。全在高纬区的大洲——南极洲,跨经度最多的大洲、平均海拔最高的大洲——南极洲,全在东半球的大洲——非洲,全在西半球的大洲——南美洲,全在北半球的大洲——欧洲和北美洲;全在南半球的大洲——南极洲,赤道穿过的大洲有——非洲、亚洲、大洋洲、南美洲,本初子午线穿过的大洲有——非洲、欧洲。

单项选择题 配伍题
单项选择题


The sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The sun has existed in its present state for about 4 billion, 600 million years and is thousands of times larger than the Earth.
By studying other stars, astronomers can predict what the rest of the sun’s life will be like. About 5 billion years from now, the core of the sun will shrink and become hotter. The surface temperature will fail. The higher temperature of the center will increase the rate of thermonuclear reactions. The outer regions of the sun will expand approximately 35 million miles, about the distance to mercury, which is the closest planet to the sun. The sun will then be a red giant star. Temperatures on the earth will become too hot for life to exist.
Once the sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the earth, it will become a white dwarf star. The sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf.
After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the earth will be dark and cold. If any atmosphere remains there, it will have frozen onto the earth’s surface.

The word "fueled" underlined in Paragraph 1 most probably means ______ .

A.powered

B.bombarded

C.created

D.pushed