The words in the Transition Phrases and Conjunctive Adverbs columns of the chart can also connect two independent clauses. In this case, use a semicolon and a comma.
In warm climate zones, water evaporates rapidly; therefore, the concentration of salt is greater.
Both the Red Sea and the Mediterranean have narrow outlets to the ocean
however, the Mediterranean's is narrower.
A few societies in the world are matriarchal; that is, the mother is head of the family.
Some English words have no exact equivalents in other languages; for example,
there is no German word for the adjective fair, as in fair play.
See Appendix B, Conjunctive Adverbs, pages 294-295, for more examples.
Coordinators
This group of transition signals includes the seven coordinating conjunctions and, but, so, or, nor, for, and yet and the five correlative ("paired") conjunctions both ... and, not only ... but also, neither . . . nor, either . . . or, and whether. . or. When coordinators connect two independent clauses, use a comma.
In a matriarchy, the mother is the head of the family, and
all the children belong to her extended family group.
In warm climate zones, water evaporates rapidly, so It he concentration of salt is greater!
Children not only need love, but they also need discipline.
When coordinators connect two words or phrases, do not use a comma.
Would you rather take a written or an oral exam?
Children need not only love but also discipline.
EXCEPTION
Some writers use a comma before but and yet even when they do not connect independent clauses to emphasize the contrast of the connected ideas.
The poem is solemn, yet optimistic in tone
See Appendix B, Coordinators, page 291, for more examples.