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Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
that I
Grammar usage guide and real-world examplesUSAGE SUMMARY
The phrase "that I" is correct and usable in written English. You can use it when referring to something that you have done or experienced, often in a dependent clause. Example: "I remember the day that I first learned to ride a bike." Alternative expressions include "which I," "that you," and "who I."
✓ Grammatically correct
News & Media
Formal & Business
Science
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
60 human-written examples
Suppose that (i ) holds.
" 'Oh, that,' I said.
News & Media
"What's that?" I pointed.
News & Media
For that, I envy.
News & Media
With that, I agree.
News & Media
"Why's that?" I asked.
News & Media
"What's that?" I asked.
News & Media
"Play that," I said.
News & Media
"What's that?" I said.
News & Media
That, I thought, was love.
News & Media
By that, I mean successful.
News & Media
Expert writing Tips
Best practice
Retain the full phrase in academic or legal writing to ensure maximum clarity and to avoid any potential ambiguity in complex sentences.
Common error
Avoid overusing the word 'that' multiple times in the same sentence, as it can lead to a 'stuttering' effect that distracts the reader. If you find yourself using it twice in close proximity, try deleting one or rephrasing the sentence using "which I" or simply omitting the pronoun.
Source & Trust
96%
Authority and reliability
4.9/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "that I" primarily functions as a complementizer or a relative pronoun followed by a first-person singular subject. According to Ludwig AI, it is used to introduce dependent clauses that provide essential information about a preceding noun or to follow reporting verbs like 'think', 'say' or 'agree'.
Frequent in
News & Media
75%
Formal & Business
15%
Science
10%
Less common in
Wiki
5%
Encyclopedias
3%
Social Media
2%
Ludwig's WRAP-UP
In conclusion, "that I" is a robust and indispensable phrase in English writing. Ludwig AI confirms its status as a grammatically correct and highly frequent construction across various domains. Whether you are reporting a speech, describing a personal experience or defining a specific object, "that I" provides the necessary structural support to connect your ideas. While it is often omissible for a swifter narrative pace, retaining it ensures precision and clarity, especially in complex or formal sentences. Writers should feel confident using it while remaining mindful of sentence rhythm and the possibility of more descriptive alternatives like "in which I" or "given that I".
More alternative expressions(10)
Phrases that express similar concepts, ordered by semantic similarity:
I
Represents the omission of the relative pronoun for a more concise and natural flow in speech.
which I
Uses a different relative pronoun often preferred for non-restrictive clauses or objects.
whom I
A more formal variant used specifically when referring to a person as the object of the clause.
in which I
Adds a preposition to specify the context, place or manner of the action.
the fact that I
Adds a noun phrase to provide more emphasis or to function as a clear subject/object.
given that I
Introduces a conditional or justificatory premise rather than just a relative connection.
wherein I
A much more formal or legalistic way to describe a situation in which something happens.
because I
Changes the relationship from relative to causal to explain a reason.
since I
Provides a temporal or causal link instead of a direct relative identification.
seeing that I
Introduces a causal observation that justifies the main statement.
FAQs
How do I use "that I" correctly in a sentence?
The phrase "that I" acts as a connector between a main clause and a subordinate clause. For example: "I remember the day that I met you."
Can I omit "that" from the phrase?
Yes, in many cases you can simply use "I". In the sentence "The book that I read was great", omitting it to say "The book I read was great" is often more natural.
What is the difference between "that I" and "which I"?
Use "that I" for restrictive clauses that are essential to the meaning of the sentence. Use ""which I"" for non-essential information, usually set off by commas.
Is "that I" considered formal or informal?
It is neutral and widely accepted in all registers. However, omitting the 'that' is slightly more informal, while using "the fact that I" is more formal.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
96%
Authority and reliability
4.9/5
Expert rating
Real-world application tested