Definition / Explanation
In many clauses after verbs such as say, think, know, believe, hope, and be sure, the word that can be omitted without changing the meaning. This kind of ellipsis is very common in speech and neutral writing. Keeping that can make the sentence slightly more formal, slightly clearer, or more emphatic, especially in longer or more complex sentences. At advanced level, the question is usually not whether omission is possible, but whether it is the best stylistic choice. In some positions, especially after prepositions, that cannot simply disappear.
Key Rules
- After many reporting and thinking verbs, that is optional: I think (that) you are right.
- Omission is common in conversation and straightforward prose.
- Keep that if it helps avoid confusion, especially in long sentences or when several clauses follow.
- After some structures, omission is less natural or impossible. For example, after a preposition, you usually need a different structure.
- Do not omit that when it is the subject of the relative clause: The book that won the prize.
Examples
- I think (that) it's fine.
- She said (that) she was tired.
- I'm sure (that) he knows.
- We hope (that) the plan will work.
- The report showed that sales had fallen.
Common Mistakes
- ❌ The book won the prize was expensive. -> ✅ The book that won the prize was expensive.
- ❌ It depends that we have enough time. -> ✅ It depends on whether we have enough time.
- ❌ She said me that to wait. -> ✅ She told me to wait. / ✅ She said (that) I should wait.