Conjunctive adverbs are adverbs that function as conjunctions when they link two independent clauses. Some common conjunctive adverbs are accordingly, also, anyway, besides, certainly, consequently, finally, furthermore, hence, however, incidentally, indeed, instead, likewise, meanwhile, moreover, nevertheless, next, nonetheless, otherwise, similarly, still, subsequently, then, therefore, and thus.
By virtue of their prevalence alone, it is clear that mood disorders do not
necessarily breed genius; indeed, 1 percent of the general
population suffer from manic-depression, also called bipolar disorder, and 5
percent from a major depression, or unipolar disorder, during their
--Kay R. Jamison, "Manic-Depressive Illness and Creativity," Scientific American
Each clause linked by a conjunctive adverb remains independent and can stand alone; therefore, if the clauses are placed in a single sentence, they must be separated by a semicolon.
Common positions for conjunctive adverbs in sentences are before the subject, between the subject and the first verb, and at the end of the sentence. Conjunctive adverbs at the beginning of a clause must be followed by a comma (and preceded by a semicolon if the clause is linked to the previous clause).
The lithium ion battery lasts longer than the NiCad battery; therefore, one lithium ion battery may suffice.
Conjunctive adverbs between the subject and the verb must be both preceded and followed by a comma.
The lithium ion battery lasts longer than the NiCad batter; one lithium ion battery, therefore, may suffice.
Conjunctive adverbs at the end of a clause must be preceded by a comma and followed by a period.
The lithium ion battery lasts longer than the NiCad battery; one lithium ion battery may suffice, therefore.