Way back in 1674, a frog helped Antoni van Leeuwenhoek make an incredible discovery. Antoni was an amateur scientist from Holland, so fascinated by microscopes {#blank#}1{#/blank#} he'd built some of his own. One rainy day, as he went for a walk, a leaping frog {#blank#}2{#/blank#}(draw) his attention to a puddle.

    Antoni collected a drop of puddle water and put it{#blank#}3{#/blank#} his microscope. He was amazed{#blank#}4{#/blank#} (see) a whole community of creatures swimming in this one drop — tiny beings no one had ever seen before.

    These tiny beings, called microbes, are everywhere: in dirt, in food and on your kitchen table. People {#blank#}5{#/blank#} (cover) in them, too.{#blank#}6{#/blank#} you were to count all the microbes on and inside your body, you would find your body has more microbes than the world has people — over 6 billion!

    Microbes can't survive on {#blank#}7{#/blank#}(they) own. They need food. After {#blank#}8{#/blank#}(settle) into a home — you, for instance — they steal vitamins and other nutrients and leave behind dead cells and poisonous liquids called toxins. Some microbes can make you sick. People usually call these ones germs{#blank#}9{#/blank#} (lucky) for you, there are more {#blank#}10{#/blank#} (help) microbes, working together to keep you healthy, than bad ones.

    Mr. James owns a company. He put an advertisement {#blank#}1{#/blank#}a newspaper for a boy to work in his office. Out of nearly fifty people {#blank#}2{#/blank#}came to apply, the man selected one and dismissed {#blank#}3{#/blank#}others.

    “I would like to know,” said a friend, “the reason you preferred that boy, who brought neither a single letter, {#blank#}4{#/blank#}a single recommendation.”

    “You are wrong,” said the gentlemen. “He had many. He wiped his feet at the door and closed the door behind him, {#blank#}5{#/blank#}(mean) that he was careful. He gave his seat immediately to an old man, showing that he was kind and {#blank#}6{#/blank#}(thought). He took off his cap when he came in and answered my questions quickly, showing that he was a polite gentleman. Everyone else stepped over the book that I {#blank#}7{#/blank#}(put) on the floor purposely. He picked {#blank#}8{#/blank#}up and placed it on the table, and he waited quietly for his turn instead of pushing and crowding. When I talked to him, I {#blank#}9{#/blank#}(notice) his tidy clothing, his neatly brushed hair, and his clean finger mails. Can't you see that these are excellent recommendations? I considered them to be more significant than {#blank#}10{#/blank#}(letter).”

    Hearing the words, the friend nodded in agreement.

    Most children with healthy appetites（食欲）are ready to eat almost anything that {#blank#}1{#/blank#}（offer）to them. A child often likes food {#blank#}2{#/blank#} it is badly cooked. The way a meal is cooked and served {#blank#}3{#/blank#}（be）the most important.

    A meal that looks {#blank#}4{#/blank#}（attract）will often improve a child's appetite. Never ask a child {#blank#}5{#/blank#} he likes or dislikes the food and never discuss likes and dislikes in front of him or allow anybody else {#blank#}6{#/blank#}（do）so. If the father says he hates fat meat in the child's hearing, he may copy this {#blank#}7{#/blank#}（behave）. At meal times, it is a good idea to let a child come back for {#blank#}8{#/blank#} second helping（一份食物）rather than give him as much as he may eat all at once. Set a good example to your kid and don't talk with your mouth {#blank#}9{#/blank#}（fill）with food. Don't allow him to leave the table at once after a meal, or he {#blank#}10{#/blank#}（learn）to eat his food hurriedly so that he can hurry back to the toys in his room. At no time should you force or fool your child to eat.