According to their morphological structure, conjunctions are divided into the following groups:

1) simple (and, or, but, till, after, that, so, where, when, etc.);

2) derivative (until, unless, etc.);

3) compound (however, whereas, wherever, etc.);

4) composite (as well as, as long as, in case, on the ground that, for the rea­son that, etc.).

Simple conjunctions remarkably outnumber compound ones. Compos­ite conjunctions give rise to debates over the possibility to consider word combinations as a part of speech.

It should be noted that some conjunctions are used correlatively: both… and. either…or, not only…but (also), neither …nor, whether …or.

As to their function, conjunctions fall into two classes:

1) coordinating conjunctions;

2) subordinating conjunctions.

Coordinating conjunctions (and, not, neither … nor, or, either…or, etc.) join words, word combinations as well as coordinate clauses in a compound sentence, or homogeneous subordinate clauses in a complex sentence, or independent sentences.

Coordinating conjunctions are divided into four semantic classes. Each class includes conjunctions that introduce a certain type of compound sen­tences:

a) copulative conjunctions: and, nor, as well as, both…and, not only…but (also), neither..nor. Copulative conjunctions chiefly denote that one state­ment or fact is simply added to another, with nor and neither expressing that relation in the negative sense;

b) disjunctive conjunctions: or, either…or, or else, else. Disjunctive con­junctions offer some choice between one statement and another;

c) adversative conjunctions: but. while, whereas. Adversative conjunctions show that one statement or fact is contrasted with or set against another;

d) causative-consecutive conjunctions: so, for. Causative-consecutive con­junctions denote consequence, result, or reason. These conjunctions indi­cate that one statement or fact is inferred from another. It should be pointed out that the conjunction for is a borderline case between a coordinating and a subordinating conjunction. When expressing cause, it semantically approaches the subordinating conjunctions as and because.

Some of the coordinating conjunctions are polysemantic. Thus the co­ordinating conjunction and may indicate different relations: cf. Jack had breakfast and left for the office (the copulative and); You started working here two days ago, and I’ve been here for five years already (the adversative and); Jog five miles every morning and you’11 be fit (the consecutive and).

Conjunction: structural and semantic classifications – Part 2