Hello everyone,
Is it correct to use a comma before ‘that’ in the below sentence?
This is used in an active sense, that is the action in the participle phrase is one
which the subject actively performs.
As I know, we cannot use a comma before ‘that’ but we can do so for ‘which’.
Thanks.
The comma helps make sense of that sentence by separating the clauses. It’s appropriate to use it, despite your ‘rule’.
However, what is the meaning of ‘that’? What subject is the third ‘is’ connected to? Could you please analyse the sentence more?
Actually, ‘This’ in the sentence refers to ‘Present participle phrase’.
Present participle phrase is used in an active sense, that is the action in the participle phrase is one which the subject actively performs.
Thanks.
‘that is’ used in this sentence is an idiom:
that is (to say)
used to say what something means or to give more information.
In that sentence, you’re supposed to have commas both before and after “that is”, not just before it.
Good catch, Jamie. 
How about this quote:
In fact, these two sounds, /ɔ/ and / ɑ/, are so similar in many parts of the United
States, that some language experts even claim that they are the same sound.
Should we use ‘that’ or ‘which’?
Thank you very much.
[quote=“Anhminh1232002”]
This is used in an active sense, that is the action in the participle phrase is one
which the subject actively performs.
Thanks.[/qu
ote]
I most respectfully suggest that you use a semicolon and a comma:
This is used in an active sense; that is, the action in the participle phrase is one which the subject actively performs.
How about this quote:
In fact, these two sounds, /ɔ/ and / ɑ/, are so similar in many parts of the United
States, that some language experts even claim that they are the same sound.
Should we use ‘that’ or ‘which’?
Thank you very much.
‘That’ is correct as written.
‘Which’ would not work in that quote.