A an the preposition A/an and the: typical errors. We don’t use the with plural nouns when we are referring to things in general: We have to protect wild animals. (referring to wild animals in general) Not: the wild animals. We don’t use the when we refer in general to something abstract or uncountable. 1 prepositions of place 2 What exactly is a preposition? A preposition is a word—and almost always a very small, very common word—that shows direction (to in "a letter to you"), location (at in "at the door"), or time (by in "by noon"), or that introduces an object (of in "a basket of apples"). 3 a and an rules 4 A preposition is a word—and almost always a very small, very common word—that shows direction, location, or time, or that introduces an object. I sent a letter to you. (To is a preposition showing direction) Someone is at the door. (At is a preposition showing location) We will arrive by noon. (By is a preposition showing time). 5 The patterns that determine which article, a or an, is conventionally used before a given word are based on phonetics, but the patterns exist in writing as well as speech. When preceding a consonant sound, a is used: "a cake," "a slice of cake." Before a vowel sound, an is usual: "an enormous slice of cake," "an appropriately enormous slice of. 6 The reason is that the articles a/an and the communicate definition or a lack thereof. We also use an instead of a when the word following begins with a vowel sound: an egg, an omelet, an institute, an honor. A will always be followed by a word that starts with a consonant sound: a box, a trampoline, a hero, a unique opportunity. 7 learn prepositions 8 Main rule: A and An are used in front of singular nouns. 9 Add the correct prepositions in set expressions. 10