Its problem is not grammatical, but idiomatic. We say take an exam, or sit for an exam, but we do not say attend an exam. A sentence may be grammatically correct and still wrong.
So you can learn that it is grammatically correct to say exams, not, as you put it, exam
No, it's having a meeting or attending a meeting (or you might be holding a meeting if you're the boss).
To have grammatically correct and pronounce the word very well.
yes
Not exactly. The correct sentence should be as follows:The class is busy in attending the examination.orThe students in the class are busy attending the examination.orThe students in the class are busy in writing their examination.
"Not like that" can be grammatically correct, depending on the context.
Yes! That is grammatically correct!
Yes, 'for free', is grammatically correct.
This is not grammatically correct. The correct form is 'you do not know', or the abbreviated 'you don't know'.
'What a drunkard you are' is a grammatically correct English sentence.
"That was wrong" is a grammatically correct sentence.
Yes, Almighty God is grammatically correct.