17．How many things can you see in the night sky？A lot!On a clear night you might see the Moon，some planets，and thousands of sparkling stars．
You can see even more with a telescope．And with bigger and bigger telescopes you can see more and more objects in the sky．And you can see those objects in more and more detail．
But scientists believe there are some things in the sky that we will never see．We won't see them with the biggest telescope in the world，on the clearest night of the year．
That's because they're invisible．They're the mysterious dead stars called black holes．
You might find it hard to imagine that stars die．After all，our Sun is a star．Year after year we see it up in the sky，burning brightly，giving us heat and light．The Sun certainly doesn't seem to be getting old or weak．But stars do burn out and die after billions of years．
As a sta's gases burn，they give off light and heat．But when the gas runs out，the star stops burning and begins to die．
As the star cools，the outer layers of the star pull in toward the center．The star squashes into a smaller and smaller ball．If the star was very small，the star ends up as a cold，dark ball called a black dwarf （黑矮星）．If the star was very big，it keeps squashing （塌縮） inward until it's packed together tighter than anything in the universe．
Imagine if the Earth were crushed until it was the size of a tiny marble．That's how tightly this dead star，a black hole，is packed．What pulls the star in toward its center with such power？It's the same force that pulls you down when you jump--the force called gravity．A black hole is so tightly packed that its gravity sucks in everything--even light．The light from a black hole can never come back to your eyes．That's why you see nothing but blackness．
So next time you stare up at the night sky，remember：there's more in the Sky han we can see!Scattered in the silent darkness are black holes--the great mystery of space．
32．According to the article，what causes a star to die？A
A．As its gases run out，it cools down．
B．It has a collision（碰撞）with other stars．
C．It can only live for about a million years．
D．As it gets hotter and hotter，it explodes．
33．Which of the following statements is NOT true？D
A．Black holes are dead stars．
B．Black holes have gravity．
C．Black holes are invisible．
D．There is nothing as mysterious as a black hole．
34．What happens AFTER a star dies？A
A．It becomes invisible．
B．It falls to Earth．
C．It gets cold with less gravity．
D．It becomes brighter and easier to see．
35．Why can't you see light when you look at a black hole？B
A．Because most black holes are so far away．
B．Because te gravity of a black hole is so strong tha it sucks the light inward．
C．Because as the star's gases burn，it stops giving off heat and light．
D．Because as a star cools，its outer layers pull in toward its center．
分析 這篇文章主要向我們介紹了一些關(guān)于宇宙中星球的天文知識(shí)．利用天文望遠(yuǎn)鏡我們可以觀察到太空中更多的物體，更為詳細(xì)地了解星星．還有一些我們看不到的星星，它們靠氣體燃燒發(fā)光，當(dāng)氣體燃盡，它們便成為被叫做黑洞的神秘死星．
解答 32．A 細(xì)節(jié)理解題．根據(jù)第四段的But when the gases run out，the star stops burning and begins to die．描述，可知當(dāng)氣體燃盡，星星便停止燃燒，我們就開始看不到它們．故選A．
33．D細(xì)節(jié)理解題．根據(jù)文章內(nèi)容，They're the mysterious dead stars called black holes，黑洞是神秘的不活躍的星星，It's the same force that pulls you down when you jump--the force called gravity．黑洞上是有引力的，A black hole is so tightly packed that its gravity sucks in everything--even light．The light from a black hole can never come back to your eyes．That's why you see nothing but blackness．黑洞是看不到的，結(jié)合選項(xiàng)，故選D．
34．A推理判斷題．根據(jù)第二段的that's because they're invisible．They're the mysterious dead stars called black holes．可知當(dāng)星星成為被叫做黑洞的神秘死星后就看不見了，故選A．
35．B細(xì)節(jié)理解題．根據(jù)倒數(shù)第二段的A black hole is so tightly packed that its gravity sucks in everything-even light．The light from a black hole can never come back to your eyes．That's why you see nothing but blackness．可知，黑洞是如此緊密，它的引力吸收一切甚至是光．從黑洞發(fā)出的光永遠(yuǎn)不能回到你的眼睛．這就是為什么你看到的只是黑暗．故選B．
點(diǎn)評(píng) 本文是一個(gè)人生感悟類閱讀理解，題目涉及多道細(xì)節(jié)理解題，做題時(shí)結(jié)合原文和題目有針對(duì)性的找出相關(guān)語句進(jìn)行仔細(xì)分析，結(jié)合選項(xiàng)選出正確答案．推理判斷題也是要在抓住關(guān)鍵句子的基礎(chǔ)上合理的分析才能得出正確答案，切忌胡亂猜測，一定要做到有理有據(jù)．
