Many English learners understand the importance of building their vocabulary, but simply memorizing words is, quite often, not enough. Memorized words are soon forgotten from lack of use. Learners who make it a habit of reading English books, however, are able to retain some of the words they learn as they come across some of the same words, again and again. Even so, it is shortsighted to focus only on individual words. After all, words come in bundles, or collocations. Already, I have used the expression “come across.” If you become familiar with words that usually go together, you can sometimes predict what a speaker is going to say. This gives you tremendous advantage when you are taking an English test. A collocation, by the way, is defined by the Cambridge Dictionary as “a word or phrase that is often used with another word or phrase, in a way that sounds correct to people who have spoken the language all their lives....” While you should continue to build your vocabulary through extensive reading, you can give yourself additional practice in English speaking and writing by also paying attention to word clusters such as the ones offered in this book.