用所给词的适当形式填空。Smoking a lot is________(harm)to your health.You’d better give it up.
—Is Jeff young ________ old? — ________.
— —She is of medium height.
Kelly _______ girl, wants to be a reporter.
-There____a number of students in our school.The number of them_____over 1000.
Lucy ______ at home and read ______ interesting book.