No Colon After a Preposition or After 'That'
The Colon
Rulebase Summary
Do not use a colon immediately after a preposition (of, in, at, on) or after the word 'that.' Let the sentence flow smoothly without punctuation interrupting after these words. The list or clause that follows is a natural grammatical continuation, not a formal introduction requiring a colon.
Morson's Rule 35 · p.25 BGGP Colon.4 · p.131 BGGP No Punctuation.5 · p.396
Examples
✗
A. The report consisted of: a summary, findings, and recommendations.
✓
A. The report consisted of a summary, findings, and recommendations.
No colon after preposition 'of' — let the sentence flow.
✗
A. He testified that: the door was unlocked and the lights were off.
✓
A. He testified that the door was unlocked and the lights were off.
No colon after 'that' — it continues the sentence naturally.
Style Guide References (3)
Morson's
Rule 35
Page 25
BGGP
Colon.4
Page 131
BGGP
No Punctuation.5
Page 396