3.But in theory, matter must behave very differently/in a very different manner inside the black hole.
　　4.The most convincing evidence of black holes comes from research into binary star systems.
　　5.Mankind may one day meet this fate.
　　四、歷年試題
　　1. 星體的密度增大到一定程度時(shí)就會(huì)發(fā)生爆炸。
　　答： The star will explode when its density increases to some extent.
　　2. 你能想象黑洞的引力有多大嗎？
　　答： Can you imagine how strong the gravitational pull of a black hole is ?
　　3. 假如有人掉進(jìn)黑洞，他會(huì)認(rèn)為很快能到達(dá)黑洞的中心。
　　答：If a man fell into a black hole, he would think that he reached the center of it very quickly.
　　4. 早在17世紀(jì)天文學(xué)家便對超新星有過報(bào)道。
　　答： Supernovae were reported by astronomers as early as in the seventeenth century.
　　5. 他已盡了全力以達(dá)到自己的目標(biāo)。
　　答： He has exerted all his strength to attain his goal.