The introduction to the Teacher's Manual for the third edition of Changes contains an extensive explanation and description of each type of activity that occurs throughout the book. For each activity type, the authors explain
what
the activity involves,
why
the activity is to be done, and
how
the activity is to be done.
In the body of the book, there are notes on every activity, giving step-by-step instructions and advice. Answers to exercises in the student book will usually vary from student to student. However, in each case the authors have provided typical possible answers.