Замените в следующих предложениях модальные глаголы их эквивалентами 1. the doctor says that you may walk. 2. the vitamins are substances which must be found in the diets of animals in order that they can utilize the organic foodstuffs to best advantage. 3. when the appetite is impaired and nausea and vomiting are common, meals must be small and be given at frequent intervals. 4. with the disappearance of symptoms the patient with infective hepatitis may leave his bed for purposes of toilet.