... in activity from one section to another. Finally, there is an answer key in the back of the book for all multiple-choice, matching, true-false, and fill- in- the-blank exercises. SECTION ONE -- - ... in the English language. In fact, the use of idioms is so widespread that an understanding of these expressions is essential to successful communication, whether in listening, speaking, reading, ... part in: to be involved in, to participate in (also: to be in on) o Martin was sick and could not take part in the meeting yesterday. o I didn't want to be in on their argument, so I remained...