Grammar: Word classes

Overview

Prepositions and conjunctions

Prepositions tell us how / when / where / why some event took place or something happened. Prepositions can be used to indicate place (in), movement (to) and time (at).

Note that when prepositions express how / when / where / why meanings, they always work together with a noun group, forming a 'prepositional phrase' (in her room, to school, at five o'clock). 

Prepositions may introduce additional information about the 'Thing' in the noun group:

Ricky rode the bike every day.
Ricky rode the bike   with   the wobbly wheels every day.
                             preposition

English has a large number of prepositions. The core meaning expressed by the majority of prepositions is about location or direction. But they are often used metaphorically rather than concretely, and often idiomatically:

Idiomatic expressions are best learned as whole chunks rather than in terms of the particular prepositions.

Prepositions do not vary in their form. They are another closed word class. 

Prepositions can also occur in the verb group in phrasal verb constructions:

Miss Lee called on Bozo to answer.
Bozo looked for a way out.

For more information on prepositional phrases, see Grammar: Groups & phrases: Prepositional phrases: Overview

For more information on phrasal verbs, see Grammar: Groups & phrases: Verb group: Structure of the verb group: Phrasal verbs

For more information on different prepositions, see Grammar: Word classes: Prepositions: Overview

Conjunctions

Conjunctions are words which are used to connect one clause to another clause in sentences. They always come at the beginning of a clause.

There are two types of conjunctions:

	linking conjunctions (and, or, but, so)
	binding conjunctions (while, before, after, because, although, if)

For more information on using linking and binding conjunctions, see:

	Grammar: Sentence: Combining clauses in a sentence: Linking clauses together (coordination)
	Grammar: Sentence: Combining clauses in a sentence: Binding clauses together (subordination)