Ключевые слова: background, blue, brace, classic, concepts, control, countdown, deadline, dental, dentist, disease, doctor, down, epidemic, equipment, finish, flow, flu, health, hospital, hour, hourglass, hygiene, illness, individual, indoors, measure, medical, medicine, minute, passing, planning, profit, progress, protection, purity, routine, safety, sand, surgical, test, time, virus, waiting, watch,