A Radiation Reality Check

關(guān)于輻射的真相

The source of radioactivity is an atom so obese that it defies the laws of attraction gluing together our material world and spits out little pieces of itself -- two kinds of particles and a stream of gamma rays, similar to X-rays. An overdose of gamma rays is like a vicious sunburn, with skin damage and elevated cancer risks, but those particles are too big to penetrate our skin, meaning that they need to be swallowed or inhaled to wreak damage. The truly fearful event in a nuclear accident, then, isn't fallout but meltdown, where the core burns through the floor and suffuses the water table. There it causes agricultural havoc and radioactive dust that you better not breathe. We're not dropping dead all together from radiation poisoning or its ensuing cancers on a daily basis because, like all poisons, it isn't the particular atom that will get you. It's the dose. And damage from radioactivity requires a much greater dose than any of us would have believed.

問題：According to the passage what ultimately causes the death of the human being ?

（A） The vicious gamma rays

（B） The quantity of radioactivity

（C） The radioactive dust

（D） The meltdown in a nuclear accident

附加一個寫作小句子：

But there is, in all this, some good news.

詞匯突破（一定仔細看） ：

1. All together = en masse

2. on a daily basis = everyday

3. ensuing 隨后的

4. havoc= mayhem 災(zāi)難

5. obese 龐大

6. vicious 這里理解為：惡性的

放射性產(chǎn)生的根源是一個太龐大的原子違背了萬有引力定律（我們物質(zhì)世界存在的基本原理）并發(fā)生分裂，釋放出兩種粒子和一束類似于X光的γ射線。過量暴露在γ射線中就好像惡性曬傷一樣，會造成皮膚損傷并提高罹患癌癥的風險，但由于粒子的體積太大，所以它們無法穿透我們的皮膚，也就是說這些粒子要被人類吞入或吸入才會造成損傷。核事故中真正可怕的不是放射性塵埃而是堆芯熔毀，堆芯熔毀能夠燒穿地表并滲入地下水。堆芯熔毀可以帶來農(nóng)業(yè)災(zāi)害和不宜吸入的放射性塵埃。人類不會因為放射性毒害或由此引發(fā)的癌癥而每天大量死亡，這是因為與所有的有毒物質(zhì)一樣，罪魁禍首不是特定的原子，而是劑量。放射性造成損傷所需的劑量遠遠超過我們通常認為的水平。