Joining words: My uncle is not only a doctor but also a pharmacist.
Joining phrases: All of these clothes are either too small or worn out.
Joining clauses: Either Monica will bring drinks, or she will bring brownies.
Correlative conjunctions are stronger than coordinating conjunctions and emphasize the relationship between the ideas being joined. Notice the difference in the following sentences:
Cats and dogs make good pets.
Both cats and dogs make good pets.
Ron or Davie found my bicycle.
Either Ron or Davie found my bicycle.
Note: Not only...but also can be split apart. Even the second half can be split. Not only cannot be split.
I like not only ice skating but also hockey. Not only is he a great singer, but he is also an actor.
Note: Be careful of the placement of the parts of the conjunction.
Confusing: Either you must bring in your permission slip or stay home. (The reader is left hanging waiting for the second clause.)
Better: You must either bring in your permission slip or stay home. (You must do one of these two actions.)
Also better: Either you must bring in your permission slip, or you must stay home.
Confusing: It was not only a long movie but also exciting.
Better: The movie was not only long but also exciting.
Better: It was not only a long movie but also an exciting one.
As you learned in the modifiers unit, watch where you put only.
Confusing: Jeremy not only won a trophy but also money.
Better: Jeremy won not only a trophy but also money.