—used as a function word to indicate connection or addition especially of items within the same class or type—used to join sentence elements of the same grammatical rank or function
2
a
—used as a function word to express logical modification, consequence, antithesis, or supplementary explanation
b
—used as a function word to join one finite verb (such as go, come, try) to another so that together they are logically equivalent to an infinitive of purpose