There are a series of English words which are frequently confused by students. This article (in the link below) aims to identify them and correct those mistakes. 1. beside vs. besides Beside means "next to" but besides means "in addition (to)", "also", "moreover" e.g. You can sit down beside me if you want. e.g. I don't like that TV programme. Besides, I don't have time to watch it. 2. classic vs. classical Classic means "best", "first-class" or "masterly" but classical means "old and established" or "traditional". e.g. His most recent novel is a classic. e.g. I don't like classical music very much. 3. official vs. officer An officer is a person with a special rank or authority in the army, navy, air force, police force or customs service. An official is a person with authority in the (local or national) government or in a trade union. e.g. My brother is a naval officer, my sister is an official on the town council. pls see the link below for more information : http://www.ompersonal.com.ar/firstcertificate2/grammar/grammar2.htm Authoritative = Able to be trusted as being accurate or true; reliable: "clear, authoritative information".

Officer is merely someone who holds an office, but generally it means someone who has been tasked with protecting or policing something, like policemen and women you might see on the street. Official refers to anyone who is in a position of authority, generally a high ranking individual. Sometimes the meaning of the two can overlap, such as at the scene of a crime as you mentioned where police officers and police officials who administer over them are at the scene. Technically, the words are synonyms for each other, but in common speech they are used in specific ways that you learn by experience. e.g. chief executive officer rather than chief executive official, or sports officials rather than sports officers.