[解析]
(1)A.细节理解题。根据第二段中They're the mysterious dead stars called black holes.(它们是神秘的死亡的恒星,被称为黑洞)和第五段中If the star was very small,the star ends up as a cold,dark ball.(如果这颗恒星很小,它最终会变成一个寒冷、黑暗的球体)可知,恒星死亡后可能会变成一个黑洞。故选A项。
(2)A.细节理解题。根据第四段As a star's gases burn,they give off light and heat.But when the gases run out,the star stops burning and begins to die.(恒星的气体燃烧时,会发出光和热。但当气体耗尽时,恒星停止燃烧并开始死亡)可知,恒星的气体耗尽时开始死亡。故选A项。
(3)C.词义猜测题。根据第五段中As the star cools,the outer parts of the star pull in toward the center.The star is squashed (挤压) into a smaller and smaller ball.(当恒星冷却时,它的外部部分会向中心靠拢。恒星被压成一个越来越小的球)可知,恒星死亡时会冷却,外部向中心靠拢,被挤压成一个越来越小的球,结合划线词所在句Imagine if the Earth collapsed until it was the size of a tiny marble (玻璃球).That's how tightly this dead star,a black hole,is packed.(想象一下,如果地球_____到只有一颗小弹珠那么大,这就是这颗死星,也就是黑洞的密度。)可猜测,此处指"想象一下,如果地球向内塌陷,直到它变成一个小玻璃球那么大",collapsed为"向内塌陷"的意思,A.Rolled.滚动;B.Ran.跑步;C.Fell inward.向内塌陷;D.Spread out.摊开。故选C项。
(4)D.推理判断题。根据倒数第二段中A black hole is so tightly packed that its gravity absorbs everything — even light.The light from a black hole can never come back to your eyes.That's why you see nothing but blackness.(黑洞是如此紧密,以至于它的引力会吸收一切——甚至光。黑洞发出的光永远不会回到你的眼睛里。所以你只能看到一片漆黑)可知,人们看不到黑洞发出的光,是因为光无法逃脱黑洞的引力。故选D项。