Mark Twain，the famous American writer，liked to play jokes on others．But once a joke 1 ndline on him．
One day Mark Twain was invited to give a talk in a small town．2 ndline lunch he met a young man，one of his friends．
The young man said that he had an uncle with him．He told Mark Twain that his uncle 3 ndline laughed or smiled，and that nobody and nothing was able to make his uncle smile or laugh．“You 4 ndline your uncle to my talk tonight，”said Mark Twain．“I'm sure I can make him laugh．”That evening the young man and his un-cle sat in the front．Mark Twain began to speak．He told several funny stories．This made everyone in the room 5 ndline．
But the old man never even smiled．Mark Twain told more funny stories，6 ndline the old man still kept quiet．Mark Twain told his 7 ndline stories．Finally he stopped.He was tired and quite 8 ndline．Some days later，Mark Twain told another friend of his about 9 ndline had happened．
“Oh，”said his friend，“I know that old man．He's been 10 ndline for years．”
