在作为人类主要能源的化石能源发生危机时，核能由于其能量密度远高于化石能源，给人类

完形填空.

     One day，a ragged(衣衫褴褛的)man with an old wallet in his hand was asking at every
door along the street for a few cents to buy something to eat.As he was complaining about his
bad fortune，he kept __1__ why those folks who had so much money were never __2__
and were always wanting more.
     “As for me，if I had only enough to __3__ and to wear，I wouldn’t want anything
more，”said the beggar.
     Just at that moment Fortune(命运女神)came down the __4__.She saw the beggar and
said to him，“Listen！I’ve long wished to __5__ you.Now，hold your __6__ and I’ll
pour this gold into it.But I’ll pour only on this __7__：All that falls into the wallet will be
 pure gold；but every piece falling upon the __8__ shall become dust.Do you understand？”
   “Yes，I understand，”said the beggar.“Then have a __9__.Your wallet is __10__，

so don’t load it too heavily.”said Fortune.The beggar was so glad that he could hardly

__11__.He quickly opened his wallet，and a __12__ of yellow coins was poured into it.
The wallet soon began to grow heavy.
     “Is that enough？”asked Fortune.“Not yet.”“Isn’t it cracking？”“Never __13__.”
The wallet was filled with so many coins that the beggar’s hands began to __14__.“Ah，
if only the golden stream would __15__ forever！I’m the richest man in the world now！
Just a little more.”said the beggar.“__16__ just a handful or two.”“There！It’s full.The
wallet will __17__.”“But it will __18__ a little more，just a little more！”
     Another piece was added and the wallet split(裂开)．The __19__ fell upon the ground
and was turned to dust.The beggar had now __20__ but his broken wallet.