people must wear helmets on bikes.
in the USA people must wear a heImet w on bikes .
[图文] More mothers now work outside the home and more fathers must help with childcare. These two special days are celebrated in many different ways. On mother's Day, people wear carnations. A red one
[图文] for the engineering profession in the USA The majority of men take up the profession throughout(3) _3_ (wear) a certain kind of clothing, eat a special kind of cereal (麦片) ,or see a movie.