then indeed you stand on shaky ground.以下是小編為大家搜尋整理的2017年職稱英語理工A考前集訓練習題，希望能給大家帶來幫助!更多精彩內容請及時關注我們應屆畢業生考試網!
The Northern Lights
The Sun is stormy and has its own kind of weather. It is so hot and active that even the Sun’s gravity cannot hold its atmosphere in check1! Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour2. These particles are called plasma, and the stream of plasma3 coming from the Sun is called the solar wind. The more active the Sun, the stronger the solar wind.
The solar wind constantly streams toward the Earth, but don’t worry because a protective magnetic field surrounds our planet. The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles. The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth’s magnetic field, the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.4
The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth’ s atmosphere at the poles. As the electrons fall to the Earth, they collide with gas molecules in the atmosphere, creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky, they create the Northern Lights and the Southern Lights.
Watching auroras is fun and exciting, but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate, flicker, or even move like waves. During solar maximum,5 auroras are seen as far south as Florida, even Mexico!6
Auroras often seem to be very close to the ground, but the lowest aurora is still about 100 kilometers above the ground, a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long, a few hundred kilometers high, but only a few hundred meters thick.
We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!詞彙： electrify /I5lektrIfaI/ v. 使帶電 aurora /C:5rC:rE/ n. 極光 steer /stiE/ v. 駕駛;導向，引向 flicker /5flikE/ v.閃爍 collide /kE5laid/ v.碰撞 plasma /5plAzmE/ n.等離子體
electron /I5lektrRn/ n. 電子 pulsate /pQl5seit/ v. 跳動 molecule /5mClikju:l/ n. 分子 Arctic /5B:ktik/ adj. 北極的註釋：
1. The sun cannot hold its atmosphere in check：太陽無法控制它自己的大氣層。 hold … in check是“控制、支配”，例如： He wants to hold the company in check through the manager’s secretary.他想通過經理的祕書控制公司。
2. move at speeds around a million miles per hour：以約 100萬英里的時速運動。 around= about。
3. the stream of plasma：等離子流
4.… the magnetic field first gets squeezed and then the magnetic field lines break and reconnect：首先，磁場受到擠壓，接著磁場磁力線斷開又閉合。 5. During solar maximum：在太陽風暴達到最高峰的期間
6. auroras are seen as far south as Florida, even Mexico!：位於極南面的佛羅里達州，乃至於墨西哥都能看到極光。 far south意為“極南面”。練習：
1. The Sun’s gravity is too weak to keep its plasma from flowing to the Earth. A Right B Wrong C Not mentioned
2. The Earth is quite safe with a magnetic field surrounding it to protect it from the attack by the solar wind. A Right B Wrong C Not mentioned
3. Some scientists are worrying about the possible disappearance of the Earth’s protective magnetic field in the future. A Right B Wrong C Not mentioned
4. The auroras are formed when the electrons falling into the Earth’s atmosphere at the poles and colliding with gas molecules in the atmosphere. A Right B Wrong C Not mentioned
5. You cannot sec the Northern Lights unless you are in Alaska or Canada. A Right B Wrong C Not mentioned
6. Tens of thousands of tourists take special trips to Norway and Sweden every year to watch the Northern Lights. A Right B Wrong C Not mentioned
7. An aurora is generally close to the ground and is very long and thick. A Right B Wrong C Not mentioned
答案與題解 :1. B 題句的意思是：太陽的重力太弱，等離子逃離太陽，流向地球。這一說法與短文第一段第一、二句表達的內容不符。句子表達的重點不是太陽的重力太弱，而是太陽太熱，其活動又太劇烈，造成等離子逃離太陽，流向地球。所以，答案是選項 B。
2. A 題句說地球相當安全，因為有磁場在高空包圍著地球，將太陽風擋在地球大氣層外面。題句表達的意思與短文第二段第一句傳遞的資訊相符。雖然短文中沒有用 safe這個詞，但是“ don’t worry because a protective magnetic field surrounds our planet”包含了 safe這層意思，所以選項 A是答案。
3. C 題句說，有些科學家擔心包圍地球起防護作用的磁場有一天會消失。短文中找不到這一資訊，所以答案是 C。
4. A 短文第二、三段解釋極光的成因。當強大的太陽風侵入地球磁場，磁場的磁力線會斷開和閉合，等離子流的`電子進入大氣層，流向極地上空，與大氣層的氣體分子發生碰撞，發出極光。題句表達的意思與短文介紹的極光成因相符，所以答案是 A。
5. B 題句的說法明顯與短文第三段的敘述不符。第四段介紹說，當在太陽風暴達到高高峰的期間，明亮的北極光甚至在位於極南面的佛羅里達州乃至墨西哥都能看到。所以答案是 B。
6. C題句說，每年有幾萬遊客專程前往挪威和瑞典觀看北極光。短文中找不到這一內容，所以答案是 C。
7. B 題句說極光通常很接近地面，又長又厚。這一說法有兩點與短文第五段的介紹不符。第一點，極光不是接近地面，而是“似乎很接近地面 (Auroras often seem to be very close to he ground)”，事實上，最靠近地面的極光離地面也有 100公里。第二點，極光不厚，“ only a few hundred meters thick”。所以答案是 B。
