This module deals with compound sentence elements (subjects, verbs, etc.) and compound sentences (two independent clauses joined together).
COMPOUND SENTENCE ELEMENTS:
Compound subjects: Mother and Father are leaving tomorrow.
Compound verbs: Mother left at noon and took a plane.
Compound direct objects: I saw a zebra and a lion.
Compound adjectives: The large but graceful dancer danced.
Any sentence element may be a compound.
Two independent clauses may be joined to become a compound sentence. The pattern is
S-V, and/or/but/nor/for/yet/so S-V.
Mother left early, but Father was late.
I knew what to do, yet I failed in my task.
He lay down on the grass, for weariness overtook him.
Notice that only a limited number of conjunctions can join compound elements or compound sentences: AND, OR, BUT, FOR, NOR, YET, SO.
These coordinate conjunctions join things of equal value. If there is a subject on the left of the conjunction, there must be a subject on the right. When coordinate conjunctions join independent clauses, a comma goes before the conjunction.
Other words that may join independent clauses are conjunctive adverbs, but these words must join independent clauses with semicolons [;], not commas [,].
Some conjunctive adverbs:
consequently for example furthermore however
instead moreover nevertheless otherwise
then therefore thus
The pattern is S-V; therefore, S-V.
Conjunctive adverbs are followed by a comma because they are interrupters.
Semicolons, like periods, may also separate two independent clauses when there is no conjunction. A semicolon indicates a closer relationship than a period does.