CONTENTS 1
Lesson 1．How Do Scien tists Discover New Truths? 1
The Subjunctive Mood 6
Lesson 2．JamesWatt and the Teakettle 14
The SubjunctiveMood （Continued） 20
Independent Reading 1:Isaac Newton and the Apple 25
Lesson 3．Robinson Crusoe's First Year on the Isle 30
Paren thetical Expressions and the Elliptical Sentences 36
Lesson 4．Robinson Crusoe's FirstYear on the Isle（Continued） 43
Sentences in the Inverted Order 47
Independent Reading 2:A Cruise Round My Isle 56
Lesson 5．Flying A Kite 60
Types of Sentences 66
Independent Reading 3:Early Experiments with Electricity 73
Lesson 6．The First Balloon Flight 76
The Perfect Participle and Participia lAbsolute Constructions 82
Independent Reading 4:Who Invented the First Adding Machine? 86
Lesson 7．A Railway Incident 90
The Perfect Infinitive and the Perfect Gerund 95
Independent Reading 5:Golden Trumpets 102
Lesson 8．Marx at Work 107
The Uses of It,As,One 114
Independent Reading 6:Marx's Personal Life 122
Supplementary Readings: 126
1．Yeast 126
2．Numbers and Numerals 127
3．Some Elementary Expressions in Chemistry 129
4．Atom Story 131
5．Broadcasting 135
6．The Origin of Rivers 140
7．The Little Match Girl 142
8．The Emperor's New Clothes 146
An Outline of Grammar 152
A List of Common Phrases 166
Irregular Verbs 184
Vocabulary 185