No, not by a long shot! You could write "They are engineers", "He is an engineer", "She is an engineer", "She/he is an engineer" (and yes, I know how awkward that is). Or you could include a name or other job title to help you-- the project supervisor is an engineer, or the project supervisors are engineers. If you are talking about a formal presentation, the subject and predicate have to agree in number.
"You are" is present tense, happening now,, while "sat" is past tense. so this sentence doesn't work. :" You are sitting writing this," although awkward is correct.
"That was wrong" is a grammatically correct sentence.
Yes, it is grammatically correct.
Yes, Almighty God is grammatically correct.
This sentence is grammatically correct.
I don't understand the question. Perhaps you mean; "Is anyone capable of writing a coherent, intelligible and grammatically-correct question?"
It is what you will hear in informal speech, but is not correct for formal writing. Try: "That is the girl.", "That is the woman.", "That is my sister.", "That is my wife.", etc. The grammatically correct form of the sentence 'That is her' is 'That is she.'
Yes. If used as an inquiry then the first letter should be capitalised and it should end with a question mark.
Yes, but it is very informal - that is not suitable for writing.
Yes, it is grammatically correct to begin a sentence with a preposition in certain cases, especially in informal or conversational writing. However, it is generally avoided in formal or academic writing.
"Not like that" can be grammatically correct, depending on the context.
Yes! That is grammatically correct!
Yes, 'for free', is grammatically correct.
Yes, it is grammatically correct; when used, it is followed by a comma. However, it is often overused in writing and shouldn't be used in excess.
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.