Today is the twins'birthday(生日). They are twelve. Jim, Mike, Kate and Bill are the twins'friends. They want to buy some presents(礼物) for them. There is a big shop near their school. It sells a lot of things. In the shop, people can buy foods, drinks and school things. The shop closes very late. So they can buy things on their way home. They buy a big cake, two boxes of color pencils, an orange yo-yo and some nice exercise books. They want to buy two dolls and two toy trains for the twins. But all the dolls and toys are too expensive.