Day 264: Correlative pairs don’t have commas.

A correlative pair is a pair of words or phrases that connects the meaning of two parts of the sentence. They must always be used in these pairs, i.e., you can’t use just the first part of the pair. Here are some examples of correlative pairs:

either . . . or

not only . . . but also

both . . . and

neither . . . nor

Now, to the point of this tip on writing mechanics. You don’t need a comma before the second part of the correlative pair. Consider this example.

广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元

Wrong: “She will either find the employee handbook in the workroom, or she will download it from the network.” [Notice the comma before “or.”]
Correct: She will either find the employee handbook in the workroom or she will download it from the network.” [This has no comma before “or.”]

Caveat: If you have a non-restrictive phrase before the second part of the pair, you may have a comma before the second part. The entire non-restrictive phrase is set apart from the sentence with commas (one before and one after).

For example: “She will either find the employee handbook in the workroom, which is on the second floor, or she will download it from the network.” The commas are required by the non-restrictive phrase, not by the correlative pair.