The expressions they use might whom they are speaking to or how well they know each other.
—I called you yesterday evening, but nobody answered. —Oh, ______ at that time.
—Do you practice how to escape from dangers every term? —Of course. Our school pays much attention to the ______ of safety.
—Are these books yours, Mike? —No, they aren’t. They belong to ______.
—I think sixteen-year-olds should be allowed to drive. —______. They aren’t serious enough at that age.
—Let’s visit the sick children in hospital and ______. —OK, let’s go.