2019年托福考试考前必看阅读试题3

阅读试题对于大家来说并不是难点，但是想要在考试中获得高分也不是件容易的事，需要我们在平时勤加练习，今天小编就为大家整理了这篇阅读试题，在坦途网托福考试频道还有很多相关的试题和考试时间计时，现在我们就来看一下这篇考试试题吧！

The spectacular aurora light displays that appear in Earth's atmosphere around the north and south magnetic poles were once mysterious phenomena. Now, scientists have data from satellites and ground-based observations from which we know that the aurora brilliance is an immense electrical discharge similar to that occurring in a neon sign.

To understand the cause of auroras, first picture the Earth enclosed by its magnetosphere, a huge region created by the Earth's magnetic field. Outside the magnetosphere, blasting toward the earth is the solar wind, a swiftly moving plasma of ionized gases with its own magnetic filed. Charged particles in this solar wind speed earthward along the solar wind's magnetic lines of force with a spiraling motion. The Earth's magnetosphere is a barrier to the solar winds, and forces the charged particles of the solar wind to flow around the magnetosphere itself. But in the polar regions, the magnetic lines of force of the Earth and of the solar wind bunch together. Here many of the solar wind's charged particles break through the magnetosphere and enter Earth's magnetic field. They then spiral back and forth between the Earth's magnetic poles very rapidly. In the polar regions, electrons from the solar wind ionize and excite the atoms and molecules of the upper atmosphere, causing them to emit aurora radiations of visible light.

The colors of an aurora depend on the atoms emitting them. The dominant greenish white light comes from low energy excitation of oxygen atoms. During huge magnetic storms oxygen atoms also undergo high energy excitation and emit crimson light. Excited nitrogen atoms contribute bands of color varying from blue to violet. Viewed from outer space, auroras can be seen as dimly glowing belts wrapped around each of the Earth's magnetic poles. Each aurora hangs like a curtain of light stretching over the polar regions and into the higher latitudes. When the solar flares that result in magnetic storms and aurora activity are very intense, aurora displays may extend as far as the southern regions of the United States.

Studies of auroras have given physicists new information about the behavior of plasmas, which has helped to explain the nature of outer space and is being applied in attempts to harness energy from the fusion of atoms.

1. What does the passage mainly discuss?

(A) The methods used to observe auroras from outer space

(B) The formation and appearance of auroras around the Earth's poles

(C) The factors that cause the variety of colors in auroras

(D) The periodic variation in the display of auroras

2. The word phenomena in line 2 is closest in meaning to

(A) ideas

(B) stars

(C) events

(D) colors

3. The word picture in line 5 is closest in meaning to

(A) frame

(B) imagine

(C) describe

(D) explain

4. The passage describes the magnetosphere as a barrier (line 10) because

(A) its position makes it difficult to be observed from Earth

(B) it prevents particles from the solar wind from easily entering Earth's atmosphere

(C) it increases the speed of particles from the solar wind

(D) it is strongest in the polar regions

5. The word them in line 16 refers to

(A) polar regions

(B) electrons

(C) atoms and molecules

(D) aurora radiations

6. According to the passage , which color appears most frequently in an aurora display?

(A) greenish-white

(B) crimson

(C) blue

(D) violet

7. The word emit in line 20 is closest in meaning to

(A) change from

(B) connect with

(C) add to

(D) give off

8. The word glowing in line 22 is closest in meaning to

(A) shining

(B) moving

(C) charging

(D) hanging

9. Auroras may be seen in the southern regions of the United Sates when

(A) magnetic storms do not affect Earth

(B) solar flares are very intense

(C) the speed of the solar wind is reduced

(D) the excitation of atoms is low

10. The passage supports which of the following statements about scientists'n derstanding of

auroras?

(A) Before advances in technology, including satellites, scientists knew little about auroras.

(B) New knowledge about the fusion of atoms allowed scientists to learn more about auroras.

(C) Scientists cannot explain the cause of the different colors in auroras.

(D) Until scientists learn more about plasma physics, little knowledge about auroras will be available.

11. Which of the following terms is defined in the passage ?

(A) magnetosphere (line 6)

(B) electrons (line 15)

(C) ionize (line 15)

(D) fusion (line 29)

BCBBC ADABA A

以上就是小编为大家整理的全部内容了，相信在我们现在的杰阶段练习题对我们来说很重要，它可以让我们了解自己对知识点的掌握情况，更有针对性的进行补充，小编会在网站对大家整理更多的考试资讯和试题，希望在今年的托福考试中大家都能取得理想的成绩！