问题
单项选择题
把下面的六个图形分为两类，使每一类图形都有各自的共同特征或规律，分类正确的一项是（）。
A.①④⑥，②③⑤
B.①②⑤，③④⑥
C.①②④，③⑤⑥
D.①②⑤，③④⑥
答案
参考答案：C
解析：本题考查一笔画问题。①②④的奇点个数是2，均可以一笔画出。图形③的奇点个数是4、图形⑤不是连通图形、图形⑥的奇点个数是4，均不能一笔画出。因此C项当选。
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把下面的六个图形分为两类，使每一类图形都有各自的共同特征或规律，分类正确的一项是（）。
A.①④⑥，②③⑤
B.①②⑤，③④⑥
C.①②④，③⑤⑥
D.①②⑤，③④⑥
参考答案：C
解析：本题考查一笔画问题。①②④的奇点个数是2，均可以一笔画出。图形③的奇点个数是4、图形⑤不是连通图形、图形⑥的奇点个数是4，均不能一笔画出。因此C项当选。
It’s certain that the following tale is a nice example that can teach us a good lesson. One day, a young man 36 begged from door to door along the street. 37 an old wallet in hand, he was asking for a few coins to buy something to eat. He kept complaining about his bad 38 and kept wondering why those who had so much money were never 39 and were always desiring more. “As for me, if I had only enough to eat and to wear, I would not want anything more." Just at that moment Goddess Fortune 40 the beggar among the crowd and approached him, greeting, “Hi, young man, I have wished to 41 you for a long time. If you open your wallet, I will pour my gold into it. But keep in mind that I will do that only on this 42 : All that falls into the wallet will be pure gold belonging to you; but every piece falling upon the ground 43 become dust, worth nothing. Are you clear?” “I see. Now I’m ready. ” said the beggar with confidence. “Then you should 44 ! It’s obvious that your wallet is a/an 45 one, so don’t load it too heavily,” said the Goddess Fortune. The excited beggar could hardly 46 to have gold. He quickly opened his wallet, and a 47 of yellow coins was poured into it. The wallet became heavier and heavier. “Is that enough? Isn’t it cracking? Will your wallet strong enough for more?” warned the Goddess. “Never 48 .It’s still strong enough now” replied the beggar firmly. The wallet was filled with so many coins that the beggar’s hands began to 49 . “Ah, if only the golden stream would 50 forever! Just a little more,” said the beggar, “ 51 just a handful or two.” “There! It’s full. The wallet will 52 .” warned the Goddess again, but the beggar insisted, “ I know it will 53 a little more, just a little more.” One more piece was added and the wallet split. The 54 fell upon the ground and became dust. The greedy beggar had now 55 but his broken wallet.
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