杰瑞与汤姆

摘要： At the entrance to the university, there is a huge rectangular billboard of size h*w (h is its height and w is its width). The board is the place wher 阅读全文

摘要： Benny has a spacious farm land to irrigate. The farm land is a rectangle, and is divided into a lot of samll squares. Water pipes are placed in these 阅读全文