There are 100 units in the book, each looking at a particular area of grammar. Some sections within each unit focus on the particular use of a grammatical pattern, such as will be + -ing (as in will be travelling): others explore grammatical contrasts, such as whether to use would or used to in reporting past events, or when we use except or except for. The 100 units are grouped under a number of headings such as Tenses and The future, and you can find details of this in the Contents. Each unit consists of two pages. On the left-hand page are explanations and examples; on the right-hand page are practice exercises. The letters next to each exercise show you which section(s) of the left-hand page you need to understand to do that exercise.
