Lesson 17 1
Text A Holipay in the Country 1
Appendix 3 Vocabu ary 3
Conversation Life and Work on the Farm 7
Word Study By 9
Grammar 1．限定动词和非限定动词 11
2．不定式的形式和特征 11
3．不定式的用法 12
4．只用to代表的不定式 16
Supplementary Reading （A）Little John at the Farm 22
（B）Machines on the Farm 22
Lesson 18 26
Text Tree-Our Best Priends 26
Conversation Do Trees Sleep？ 35
Word Study Fall 38
Grammar 1．不带to的不定式 39
2．“for+名词或代词宾格+不定式”的结构 41
3．What，Which，Who，Whether，How，Where或When+不定式 42
4．Too+形容词或副词+不定式 42
5．以介词结尾的不定式短语 43
Supplementary Readiny A Tale of a Giant Tree 48
Lesson 19 52
Text Butterflies 52
Conversation Farmers Enemies 56
Word Study Look 59
Grammar 1．进行不定式 60
2．完成不定式 61
3．完成进行不定式 62
4．不定式的被动态 62
5．形容词和副词的比较等级 65
Supplementary Reading （A）Insects 74
（B）Entomology 75
Text The Greatest Evolutionist 79
Lesson 20 79
Conversation Going to a Bookstore 83
Word Study Bring 89
Grammar 1．Be+不定式 91
2．形容词或副词+Enough+不定式 93
3．In Order To和So As To 93
4．So…As To和Such（…）As To 94
5．后跟不定式作宾语的动词 95
6．“分裂不定式” 95
Supplementary Reading Darwin on the Beagle 103
Lesson 21 106
Text Two Poems 106
Conversation Little and Small 113
Word Study In（1） 115
Supplementary Reading （A）Spring 118
（B）The Wind 119
Review Exercises（Lesson17一Lesson20） 122
Lesson 22 128
Text The Yellow River 128
Conversation Swimming in the Canal 139
Word Study Break 142
Grammar 1．分词的形式和特征 144
2．分词的用法 145
Supplementary Reading The Importance of Rivers 157
Lesson 23 161
Text Three Fables 161
1．The Fox and the Grapes 161
2．The Shepherd Boy 162
3．The Swallow and the Other Birds 162
Conversation Fables Teach Lessons 171
Word Study Give 174
Grammar 1．简单现在分词的被动态 176
2．完成的现在分词的主动态 176
3．完成的现在分词的被动态和过去分词 177
4．That，Those和One，Ones用作名词的替代词 178
Supplementary Reading The Treasure in the Orchard 186
Lesson 24 192
Text The Soft Machine 192
Conversation Seeing the Doctor 195
Word Study Carry 198
Grammar 1．分词和不定式某些用法的比较 200
2．数词 201
Supplementary Reading Water:for Life 211
Lesson 25 214
Text Living Organisms and Man 214
Conversation Asking for Advice on Rose-Growing 222
Word Study In（2） 224
Grammar 1．独立主格分词结构 226
2．副词的分类 228
3．副词的位置 229
（B）The Animals Called Mammals 233
Supplementary Reading （A）Where Plants Grew 237
Lesson 26 243
Text Louis Pasteur 243
Conversation Pasteur and Germs 252
Word Study Turn 254
Supplementary Reading Themas Alva Edison 259
Revlew Fxercises（Lesson 22一Lesson 25） 262
Lesson 27 266
Text Madame Curie 266
Conversation China Daily 274
Word Study Take 276
Grammar 1．动名词的形式和特征 278
2．动名词的用法 279
3．前面带逻辑主语的动名词结构 281
Supplementary Reading The Curie Family 287
Lesson 28 291
Text Memory 291
Conversation Study and Exercise 296
Word Study As 297
Grammar 1．完成动名词 299
2．动名词的被动态 300
3．名词化动名词 301
Supplementary Reading （A）Seasons and Human Intelligencc 306
（B）Asking for Trouble 307
Lesson 29 310
Text A Letter o? Reading（Partl） 310
Conversation Posting Letters and Parcels 317
Grammar 1．动名词和现在分词作定语的区别 322
2．后跟动名词作宾语的动词 323
3．动名词和不定式的比较 324
Word Study For 330
Supplementary Reading How to Write Letter in English（Part 1） 333
Lesson 30 337
Text A Letter on Reading （Part 2） 337
Conversation The Best Ways to Study English 346
Word Study Go 349
Supplementary Reading How to write Letters in English（Part 2） 355
General Review Exercises 358
Appendix 1 An Alphabetical List of Irragu ar Verbs 369
Appendix 2 Index 377