Editing Tip: Correlative Conjunctions

Correlative conjunctions are pairs of phrases or words that are used to link two ideas. One correlative conjunction, “both…and,” was discussed as part of a previous editing tip. Other common examples include “either…or,” “neither…nor,” “not only…but also,” and “not…but.” Here, we review the use of these additional correlative conjunctions and how they can facilitate your technical writing.

Correlative conjunctions are often used to compare, contrast, or link two concepts. Several examples are below:

• either/or: The animals were administered either vehicle or drug.
• neither/nor: The slurry was affected neither by heat treatment nor by irradiation.
• not only/but also: The additive acted not only as a surfactant but also as a reducing agent.
• not/but: The nanoparticles were not red but blue.

Note that a comma is not necessary between the two components of a correlative conjunction. Furthermore, both parts of the correlative conjunction must be used in the sentence to properly convey the intended meaning. Finally, careful attention should be given to the placement of the two components of the correlative conjunction within the sentence to ensure grammatical parallelism.

• Chemical monolayers allow not only surface functionalization but also provide stabilization. (Incorrect)
• Chemical monolayers not only allow surface functionalization but also provide stabilization. (Correct)

In the first example, not only is followed by “surface functionalization,” while but also is followed by “provide stabilization.” These quoted phrases are not grammatically equivalent (the former is an object, whereas the latter is a predicate). In contrast, in the second example, not only is followed by “allow surface functionalization,” and but also is followed by “provide stabilization.” These phrases are grammatically equivalent because they are both predicates (i.e., statements containing a verb).

Need help deciding where to place a correlative conjunction to ensure parallelism? When a correlative conjunction is used correctly, the sentence should still be grammatically correct if the entire correlative conjunction and the text that it encloses are removed. For example, when everything between and including “not only…but also” is removed from the sentence “Chemical monolayers not only allow surface functionalization but also provide stabilization,” we get “Chemical monolayers provide stabilization,” which is still grammatically correct (albeit altered in meaning).

Finally, watch out for subject-verb agreement when using correlative conjunctions. For “either...or” and “neither...nor” statements describing two subjects or two objects, the verb should agree with the subject or object that appears last (i.e., closest to the verb) in the sentence:

• Neither the nanoparticles nor the drug was cytotoxic.
• Neither the drug nor the nanoparticles were cytotoxic.

In the first example, the verb is singular to provide agreement with “drug,” whereas in the second example, the verb is plural to agree with “nanoparticles.”

We hope that this editing tip of the week will help you to use correlative conjunctions with confidence in your writing. If you have any comments or questions, please email us at [email protected]. We wish you the best!