阅读理解

    A man had a little dog, and he liked it a lot. He would pat (拍) its head, put it on his knee and talk to it. Then he would give it some food from his own plate.

    A donkey (驴子) looked in through the window and saw the man and the dog.

    " Why doesn't he choose me as his pet?" said the donkey. "It is not fair. I work hard, and the dog only shakes its tail, barks and jumps onto the master's (主人) knee. It is not fair. "

    Then the donkey said to himself, "If I do what the dog does, the master may choose me as

his pet. "

    So the donkey ran into the room. He brayed (嘶叫) at the top of his voice. He shook his tail so hard that he knocked over a jar on the table. Then he tried to jump onto the master's knee.

    The master thought the donkey was maniacal , and he shouted, "Help ! Help ! "

    Some men came running in with sticks in their hands and they beat the donkey until he ran out of the house.

"I only did what the dog did, " said the donkey, "and yet they still regard the dog as their pet and they beat me with sticks. It is not fair. "

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“人间处处倡民主，天上谁人奉玉皇。一朵红云旗五色，惊传飞艇上天堂。”这一情景最早可能出现于（  ）

用数学归纳法证明不等式 $1+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+K+\frac{1}{\sqrt{n}}<2\sqrt{n}\left(n\in N*\right)$