Some men are wearing bright yellow shirts that say "City Sights NY." They sell tickets for double-decker（双层） buses that go around the city daily. Riders can hop（跳） on and off when and where they want. Men in white shirts push blue trash cans on wheels. The men sweep up（清扫） all the trash on the pavement. A man pedaling a yellow pedicab with two rear wheels rides by. The pedicab is a big tricycle. It has an awning（阳篷；遮篷） to shade riders. Two riders can sit in the seat behind the cyclist. He takes them on a tour of the city. A security guard stands in a small city park. He wears a blue shirt and black pants. He is friendly and helpful. Cab drivers are everywhere. They drive their yellow cabs all over the city. Day and night, thousands of New Yorkers hail（示意...停下） the cab drivers. They drive quickly but safely.