couldn't grinning

Hi,
Can I write: No. Say this.

It was very funny. I couldn't stopping grinning.

Clive

Hi,

Isn't "couldn't stop laughing" is better than "grinning'?

Laughing is when you are making noise - ha ha ha ha
Grinning is a big smile (no noise)
Parsing:

I could not stop laughing.
I = subject
could = modal (auxiliary) verb
not = adverb

stop (infinitive main verb, with modal "could")
laughing / grinning - gerund, present participle of verb laugh, grin used as a noun, the direct object of the verb stop)
I c

Hi Vincent,
I've mentioned to you before that the question 'Can I write . . . ' is not the same as 'Is it natural to write . . . '.
I recommend that you use the latter phrase.

Best wishes, Clive

How about this?

I couldn't stop smiling.

Hi,

It's fine.

Clive