The correct phrase is "Are you open today?" This is because the word "open" is being used as an adjective to describe the state of a business or establishment. In contrast, "Do you open today?" would typically be used to inquire about the specific action of opening something, rather than the general operational status of a business.
No, it is more correct to say, "What day is it today?"
It is grammatically correct to say , "I am in school today." This is because you are in the building, not at the building.
Yes.
Yes, "starting from today" is correct. It indicates that something is beginning on the current day.
Yes, that sentence is grammatically correct.
It is correct, but it would be nicer to use the baby's name, as in "How is Johnny today?"
"We were informed it will be corrected today" is a correct sentence. However, it might sound a little better to say "We were informed that it will be corrected today."
Yes, of coarse.
Yes, by the end of today is correct. It's not a complete sentence, though.
Wednesday morning, it is correct to say I have not seen him for one day. Wednesday afternoon, or by working day end, it is correct to say I have not seen him for two days
Yes, you can say that; we've got today to get this job done.
Open-minded is "d'esprit ouvert" is "ouvert d'esprit" (both are correct) in French.