［英语写作概要］Chapter 19: Using Prepositions Correctly

　　Some verbs in English are paired with a particular preposition to create an expression. Each of these expressions has a particular meaning. Even though there are often two or more prepositions paired with the same verb, each expression has a different meaning and they cannot be used interchangeably. Look at, look for, and look up have the same verb but three different prepositions. The phrases have different meanings and you cannot use look up when you need look for in your sentence. Study the material in Chapter Nineteen carefully and use the chapter as a reference tool when you need to.