Yes. "Pavement" is what Americans call a "sidewalk."
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'.
That sentence is grammatically correct.
No.
The correct grammar is "Between you and me."
"Roger and I appreciate what you did" is correct grammar
The grammar in the question is correct.
Yes. What is not correct is your putting the article "a" before grammar.
The correct grammar for this sentence is: When did your friend come?
Yes, 'you were correct' is perfect grammar. An example sentence: You were correct when you said that a tomato is a fruit.
that is correct grammar
Yes, this sentence is correct grammar.
That sentence is grammatically correct.