Good grammar is very important in order to not be misunderstood.
I went to a good grammar school.
Your grammar is appallingly atrocious.
In a sentence grammar can be endings or spelling
The grammar of this sentence is beyond phenomenal.
No. It should be "Is the grammar right in this sentence?"
no_____If the sentence is You do do that (meaning You are in the habit of doing that) the grammar is perfectly correct and the sentence 'does have correct grammar'.
If you are writing proper grammar you should not use 'then' at the beginning of a sentence.
No.
sentence
There is no such thing as an "extended sentence" in grammar. "Extended sentence" is a legal term, not a grammatical term.
That sentence is grammatically correct.
There is no sentence in the question on which to base an opinion.
The correct grammar is "Between you and me."
"Roger and I appreciate what you did" is correct grammar