Passage 3 How Clothes Are Made

Unit Thirty-five The Man's Invention

Passage 1 The Invention of Wheels

Passage 2 Making of Paper and Pencil

Passage 3 The Invention of Bicycles

Passage 4 How Did Stamps Come into Use

Unit Thirty-six The Animal World（Ⅰ）

Passage 1 Animal Mimics

Passage 2 The Frog That Changes Colour

Passage 3 Different Groups of Animals

Passage 4 The Animal Without a Head

Unit Thirty-seven The Animal world（Ⅱ）

Passage 1 Insects

Passage 2 Ants

Passage 3 Fishes

Passage 4 Reptiles

Unit Thirty-eight The Animal World（Ⅲ）

Passage 1 Birds

Passage 2 Mammals

Passage 3 The Biggest and the Gentlest

Passage 4 The World of Microbes

Unit Thirty-nine The Balance of Nature

Passage 1 The Balance of Nature

Passage 2 The Squirrel and The Acorn

Passage 3 The Food Chain

Passage 4 Our Best Friends-Trees

Unit Forty Plants（Ⅰ）

Passage 1 Plants

Passage 2 Different Types of Leaves

Passage 3 Different Types of Stems

Unit Forty-one Stories of Nature

Passage 1 The Story of Raindrop

Passage 2 Water,Steam and Ice

Passage 3 The Birth of a Volcano

Passage 4 Terrible Earthquakes

Unit Forty-two Light

Passage 1 Light

Passage 2 How Light Travels

Passage 3 Reflection of Light

Passage 4 Shadows

Unit Forty-three Heat

Passage 1 What Gives Heat?

Passage 2 Heat Travels by Conduction

Passage 3 Heat Travels by Convection

Passage 4 Shadows

Unit Forty-four Sounds

Passage 1 Are Sounds Useful or Harmful

Passage 2 How Do We Make Sounds?

Passage 3 How Does Sound Travel?

Passage 4 Sound Has Speed

Unit Forty-five Atoms and Molecules

Passage 1 Leaning about Molecules

Passage 2 Molecules Pull

Passage 3 Structure of the Atom

Passage 4 Nuclear Energy

Unit Forty-six Exploring the Space

Passage 1 The Sun and the Stars

Passage 2 Air and the Space

Passage 3 The First Men on the Moon

Unit Forty-seven Social Facts

Passage 1 Bells on Your Ears

Passage 2 The Rain Dance?

Passage 3 Can You Vote?

Passage 4 Rich Countries and Poor Countries

Unit Forty-eight Schools and Education

Passage 1 Why Do Children Go to School?

Passage 2 Early American Schools

Passage 3 The School onWheels

Passage 4 Book in Chains

Unit Forty-nine Trade

Passage 1 Let's Trade

Passage 2 Stone Money,Feather Money

Passage 3 Walking,Talking Ads

Passage 4 Different Kinds of Money

Unit Fifty Communication

Passage 1 Forms of Communication

Passage 2 Radio

Passage 3 Send a Message

Unit Fifty-one Festivals

Passage 1 Christmas Day

Passage 2 Spring Festival

Passage 3 April 1st

Passage 4 New Year's Eve

Unit Fifty-two Signs

Passage 1 Signs in the Desert

Passage 2 Something for Nothing

Passage 3 Sign Language

Unit Fifty-three Primitive Methods of Counting

Passage 1 A Stone for Sheep

Passage 2 A Dusty Way to Count

Passage 3 The Rope Stretchers

Passage 4 The Year That the Barn Burned Down

Unit fifty-four Modern Technology

Passage 1 The Machine That Knows the Answers

Passage 2 The Structure of a Computer

Passage 3 Telephone

译文

词汇

Unit One About Myself

Passage 1 My Family

Passage 2 My Room

Passage 3 My Foreign Friends

Passage 4 Our House

Unit Two Our School

Passage 1 Our Classroom

Passage 2 Our School Garden

Passage 3 Our English Teacher

Passage 4 Our Library

Unit Three Learning English

Passage 1 The English Language

Passage 2 Two Languages Or One

Passage 3 How to Use a Dictionary

Unit Four The United States

Passage 1 The Early Days of the United States

Passage 2 Schools in the U.S

Passage 3 The Climates of the United States

Passage 4 The Capital of the United States

Unit Five The United Kindom

Passage 1 The Weather in England