When you use paired conjunctions to connect two words or phrases in a sentence, you need to keep parallelism in mind. What is parallelism? Whenever you connect two items in a sentence with a conjunction, those two items need to be “parallel.” That means the same grammatical structure (noun, verb, adjective, clause, etc.) should follow each part of the paired conjunction. Look at the following examples.

Notice that the words or phrases connected by the paired conjunctions have the same word form (or part of speech):

	Both	weight loss	and	better posture	are benefits of being physically fit.
		noun phrase		noun phrase

Being in good shape	not only	improves your heart health	but also	increases your self-image.
		verb phrase		verb phrase

If you can't go to the gym, try	either	taking a short, fast walk	or	running up and down the stairs.
		gerund phrase		gerund phrase

For some people, the road to getting into shape is	neither	short	nor	easy	, but it’s worth it.
		adjective		adjective

Another thing to keep in mind when you use paired conjunctions is the placement of the paired conjunction in your sentence. Look at the two sentences below. In the first sentence, the paired conjunction is placed correctly. In the second sentence, it is not. Why? What’s the difference?

In this example, we are trying to use the paired conjunction to connect two adjectives: "strong" and "flexible". As a result, we need to put part 1 of the paired conjunction "not only" immediately before the first adjective "strong", and part 2 of the paired conjunction "but also" needs to go immediately before the second adjective.