目录 God-made Objects and Man-made Objects上帝创造的东西和人类制造的东西Plants 植物Are They Insects? 它们是昆虫吗?You Hear Sounds 你听到的声音Different Animals 不同的动物Mammals 哺乳动物How Are Animals Different? 动物有哪些不同?How Do Animals Grow and Change? 动物是怎样成长变化的?Keeping up with the Dinosaurs 关注恐龙Black Widow Spider 黑寡妇毒蛛Starfish 海星Personal Safety 个人安全Your Body Digests Food 身体如何消化食物The Body Needs Oxygen and Gives off Carbon Dioxide身体需要氧气并排出二氧化碳How to Care of the Teeth 如何保护好牙齿Water as a Solid 固态的水Chemical Change 化学变化Molecules, Atoms, and Element 分子、原子和元素From Electrons to Electric Current 从电子到电流Rainstorms, Thunder and Lightning 暴风雨和雷电Stars We See 我们看到的星星Comparing Earth and Venus 比较地球和金I Love My Country 我爱我的祖国A Nation of Immigrants 移民之国Symbols of My America 美国的标志Yellowstone Park on Fire! 黄石国家公园着火了!Citizens Now 现在是公民了Great People 伟大的人Alexander Graham Bell 亚历山大?格雷厄姆?贝尔A Great Woman 一位伟大的女性Save the Earth! 拯救地球!Save the Turkeys! 拯救火鸡!Sweet Home 温馨的家Message in the Sky 来自天上的信号Merry-go-rounds 旋转木马Scarecrows Then and Now 稻草人的发展史Baseball 棒球Basketball 篮球Floor Exercises for Gymnasts 自由体操Libraries 图书馆News Magazines 新闻杂志Fun with Photography 摄影的乐趣The Civilizations of Maya 玛雅文明The Farming Revolution 农业改革Words Around the Nation 各的语言Sight Words 常见单词Consonant Blends 辅音连读Clean up the Fragments 整理残缺句子Letter Writing 写信Personal Narrative 自我描述Nothing but Net 球网Tennis Lingo 网球术语Basketball Talk 篮球大家谈Before the Game 比赛前Pregame Warm-up 赛前热身Place Value 数字的位值Rounding: Hundreds and Thousands 百位和千位的四舍五入Two Ways to Pay Cent & Dollar 用美分和美元支付的两种方法Number Signal 数字提示Estimating 概算Multistep Problems 多重运算题Problem Solving 应用题Snack Time! 零食时间Fraction and Decimal Equivalents 分数和小数的等式
内容摘要 Plants 植物 Roots Roots are the part of the plant that is in the ground. The roots of the plant hold the plant in the ground. On each root are tiny root hairs. These tiny root hairs grow into the soil. They take in water and minerals. The plant uses water and minerals to make food. Without water and minerals, the plant cannot grow. Stems Now look at a plant’s stems. These stems are like tiny pipes. Water and minerals can travel through the stem. The stem takes water and minerals to the leaves, where the plant’s food is made. Stems are many different sizes. The big tree trunk is a stem. The stem of a cabbage plant is so short that you may not see it. Vines are a kind of stem. The tiny tubes in the stem of a celery plant are easy to see. Leaves The leaves of green plants have tiny openings in them. To see these openings, you will need the help of a microscope. A microscope makes things look much bigger than they really are. The tiny openings are important to help the plant grow. Carbon dioxide, a gas from the air, enters the leaf by the openings. Carbon dioxide is given off by people and animals when they breathe. When plants use carbon dioxide, they give off a gas called oxygen. People and animals need oxygen to live. Some of the water in the plant is given off through the leaves. Carbon dioxide goes into the leaves of the plant through tiny openings like those in this picture. Food storage parts You have learned that all green plants make food. You know that the plants use part of the food they make. This food is used to grow new leaves and roots. What happens to the rest of the food? God made green plants in a special way. All extra food is stored somewhere in the plant. Some plants such as lettuce store their extra food in the leaves. Many plants such as beets and carrots store food in their roots. The celery plant stores food in its stem. Corn, beans, and peas store food in their seeds. Still other plants store food in their fruit. Could you say, then, that you had roots, stems and leaves for dinner? stem【stem】茎,(树)干 Some wild vines ran up the stems of the corn. 一些野生的藤条缠绕着玉米杆往上长。 相关词leave [li:v] n.叶; root [ru:t] n.根; branch [brɑ:nt?] n.树枝;分支 trunk【tr??k】树干 The trunk of this tree is more than three meters thick. 这棵树的树干有3米多粗。 相关词bole [b?ul] n.树干;leaf [li:f] n.叶子; bud [b?d] n.芽 cabbage【 k?bid?】甘蓝菜,卷心菜 My brother likes to eat cabbage. 弟弟喜欢吃卷心菜。 相关词celery [ sel?ri] n.芹菜; spinach [ spinit?] n.菠菜; leek [li:k] n.韭菜 picture【 pikt??】画;画像;图片;照片 This picture vividly provides the condition of life in China at that time. 这幅图片生动地描述了那个时期的中国生活。 相关词portrait [ p?:trit] n. 肖像画; painting [ peinti?] n.油画; portray [p?: trei] v.描绘
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