English grammar
Conjunctions

Conjunctions express a variety of logical relations between items, phrases, clauses and sentences. The principal coordinating conjunctions in English are: and, or, but, nor, so, yet, and for. These can be used in many grammatical contexts to link two or more items of equal grammatical status, for example:

There are also correlative conjunctions, where as well as the basic conjunction, an additional element appears before the first of the items being linked. The common correlatives in English are:

Subordinators make relations between clauses, making the clause in which they appear into a subordinate clause. Some common subordinators in English are:

Subordinating conjunction generally comes at the very start of its clause, although many of them can be preceded by qualifying adverbs, as in probably because..., especially if.... The conjunction that can be omitted after certain verbs, as in she told us (that) she was ready. (For the use of that in relative clauses, see § Relative pronouns above.)
oulipo:avoid_letter[o], combination:repeat_prompt