Tom has a strong and faithful(忠诚的) dog, Bruce. The dog likes playing with Tom. Sometimes he also follows Tom's father to work.

    One morning when Tom's father worked in the field, he took off his coat and put it on the ground under a big tree. He turned to the dog and said, "Watch my coat, Bruce!"

    Bruce sat down on the coat. Later Tom's father remembered he had to buy some food. So he hurried to the shop. After shopping, he went home directly and forgot all about his coat and the dog.

    Late in the evening Tom looked for his dog everywhere in the house, but he couldn't find him. At this time Tom's father suddenly remembered his coat and the dog. He went back to the tree at once. He found that Bruce was still sitting on the coat!

    Mark Twain was an American writer. One day he went to a city by train. He wanted to see one of his friends there. He was a very busy man, so he usually forgot something.

    When he was on the train, the conductor asked him for his ticket. Mark Twain looked for the ticket here and there, but he couldn't find it. The conductor knew Mark Twain. She said. “Show me your ticket on your way back. And if you can't find it, it doesn't matter.”

     “Oh, thank you!” said Mark Twain. “But I must find the ticket. If I can't find it, how can I know where I'm going?”

根据短文内容，判断正误

    What was discovered by accident? The answer is penicillin (青霉素). It kills germs. By killing germs, it saves lives. Suppose you are sick. You go to a doctor. She examines you. She says you have a “staph” infection (葡萄球菌感染). She gives you some medicine. You take it. The medicine knocks out the staph. Soon you are well. Before penicillin, this would not happen. Staph was almost sure death.

    Everyone wanted a medicine. Laboratories worked day and night. They grew the staph in small dishes. Then they tried to kill it. Nothing worked.

    The laboratory dishes had covers on them. They kept things from falling into dishes. Molds (霉菌) were a big worry. They are always in the air. You can't see them. They're too small. There are thousands of different molds. Molds can make an experiment (实验) fail. That's why dishes are covered.

    Dr. Alexander Fleming was working to kill the staph germ. He worked for years. One day he took a cover off a dish. He looked inside. There was a thick growth of staph germ. There was also some mold. Then he saw something strange. Where the mold was, there was no growth of staph. This is what Fleming probably thought. “By accident, I found a mold to kill the dreaded staph.”

    This is how penicillin was found. But here's the real miracle (奇迹). There are thousands of kinds of molds. But only one kind can kill staph. The mold must have fallen into the dish a few days before. The cover was probably off only a few seconds (秒). In those few seconds the right mold fell into the right dish. Another man might have thrown the dish away. But Fleming was very careful and smart. He understood what the mold did. How lucky the humans were!

根据短文内容，选择最佳答案

    Some people have a very poor sense of direction. Unluckily, I am one of them. I have visited a place many times but I may still get lost there the next time.

    When I was a little girl, I never dared to ask strangers the way. And so I used to walk around in circles and hope that by chance I would get to the place I was going to.

    Now, I am no longer too shy to ask people for directions, but I often receive useless or ever wrong information. So I try to avoid giving people wrong directions. It anyone asks me the way somewhere, I would say, "Sorry, I am a stranger here."

    Once on my way to work I was stopped by a man. He asked me if I could tell him the way to the Friendship Building. I gave him my usual reply. But just as I walked on only a few steps, I realized that he had asked the way to my office building. However, I had no time to turn back and look for him. I hurried to meet someone at my office and I didn't want to keep him waiting.

    When I just got to my office, the secretary showed in the man who had asked me for directions. Imagine how awkward I was and how surprised he was when we saw each other at the first sight!