My friend Mr. Smith is a famous doctor and has a hospital. So he has enough money to travel all over the world. And he's been to a lot of places of interest. He likes to play with children and has a lot of little friends. They often ask him to tell them all kinds of funny things he saw. It makes them happy and his room is always full of children when he's free.

    It was my little son's seventh birthday yesterday. The boy wanted to ask his old friend Mr. Smith to the party. He called Mr. Smith himself and told him about it. The doctor accepted his invitation happily.

    Mr. Smith came on time, with a nice present in his hand. After dinner the children sat around the traveler and asked him to tell them some funny stories. Mr. Smith agreed and his stories made them laugh again and again. At last he told them the funniest story. He said, “Once I reached a city on a foggy day. The fog was the thickest in the world…”

    “Please wait a moment, Mr. Smith,” said my son, “It's said that the fog in London is the thickest in the world.”

    “You're right, my clever boy.” said the funny doctor.” The city had much fog that day…” “What's it, then?” the boy couldn't wait to ask again.

    “The fog was so thick that I couldn't see it at all.” the funny doctor said with a smile.