When is it wrong to use a comma?

Do not use a comma

before an essential or restrictive clause, that is, a clause that limits or defines the material it modifies. Removal of such a clause from the sentence would alter the intended meaning.

The switch that stops the recording device also controls the light.

between two parts of a compound predicate

The results contradicted Smith's hypothesis and indicated that the effect was nonsignificant.

to separate parts of measurement

8 years 2 months
3 min 40 s

(adapted from the fifth edition of APA's Publication Manual, © 2001)

Removing Bias in Language
Disabilities
Race & Ethnicity
Sexuality

Electronic Media
Electronic Media and URLs
Electronic Media Spelling Guide

Authorship Aids
Ethics of Publication
Determining Authorship: Students

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