That’s what the New York policeman said when asked how to get to Carnegie Hall.
Now, leaving aside the largely forgotten English spelling ‘Practise’ for the verb — the American ‘Practice’ has taken over for both verb and noun — ‘To practice’ has two meanings. It can mean to do something, and it can mean to rehearse doing it. A qualified Doctor practices medicine; he does it ‘for real’. A medical student might be said to practice medicine, meaning that he’s only trying it out, not yet practicing in the other sense.
Got that? Yes, it can be confusing. When my cousin was considering marriage to a Nepalese Muslim she had met, I asked my Aunt ‘Do Muslims practice polygamy here in England?’ ‘They not only practice it,’ she said, ‘They do it!’. My uncle looked up from his newspaper and murmured ‘I should think practicing it would be more fun.’