"Is he at office?" is in fact correct, but a very old fashioned way of making that statement.
A more current way would be "Is he in the office?" or "Is he in his office?"
No, the correct statement is: That is mine.
Yes, it is correct to say "you are correct." It acknowledges that the other person's statement or opinion is accurate.
No, the correct statement is "Are you going to school?" using the verb "are" instead of "is."
Are your children coming home? is grammatically correct.
One is not "more correct" than the other: to you and meis correct, and to you and I is barbarously wrong.
Yes that is a correct sentence, as long as you have identified who "he" is in a previous statement.
No, the correct statement is: That is mine.
The proper phrase would be "Out of the office due to death in the family" Bereavement is an emotion or state of being emotional and cannot be used in this way.
principal's office is correct
Yes, it is correct to say "you are correct." It acknowledges that the other person's statement or opinion is accurate.
No, the correct statement is "Are you going to school?" using the verb "are" instead of "is."
are you at the office
If it is the office of one nurse, this is correct - nurse's office. If it is the office of a group of nurses, this is correct - nurses' office.
Are your children coming home? is grammatically correct.
A statement that is factually correct and does not mislead.
That is correct.
No. It could be: There was no complaint from the area. Or: There were no complainsts from the area.