It is a rainy (阴雨的) day. A train stops at a small {#blank#}1{#/blank#}. A man is on the train and he feels hungry (饥饿的). He looks out of the window (窗) and sees a shop. A woman is {#blank#}2{#/blank#} cakes in the shop and the cakes look {#blank#}3{#/blank#}. The man wants to {#blank#}4{#/blank#} a cake, but the shop is a little (有点) {#blank#}5{#/blank#} from the train. The man doesn't want to walk in the rain. Then he sees a boy. The boy is about five {#blank#}6{#/blank#} old. He's playing near the window. “Come here, boy!” says the man, “Do you know how {#blank#}7{#/blank#} the cake is?” “One dollar for one.” says the boy. The man gives the boy two dollars and asks him to buy {#blank#}8{#/blank#} cakes. “One is for you and the {#blank#}9{#/blank#} is for me,” he says to the boy.

    After some time, the boy comes back. He's eating a cake. He {#blank#}10{#/blank#} the man one dollar. “Sorry, there is only one cake left (剩余). I eat the cake and here is one dollar back,” says the boy.

—On Saturday evening.

    We do not know when people invented wheels. But once it was invented, knowledge of the wheel{#blank#}1{#/blank#}quickly across the world. It is easy to move things with wheels. The first example of wheels dated from about 3. 500 to 3. 000 BC. The cart or wagon was the first vehicle which had wheels. At that time, they were pulled by humans or animals. Today, there are still carts drawn by animals in many countries. These carts are mainly used to move things or{#blank#}2{#/blank#}people. Around 2, 000 BC, the chariot(双轮敝篷马车)appeared. It moved even faster than the cart, so it soon became an important{#blank#}3{#/blank#}in the war and later was introduced to other ancient countries, such as Egypt, Persia, Greece and Rome.

    The invention of wheels is very important to the{#blank#}4{#/blank#}of new transportations. Without wheels, the invention of bicycles, motorcycles, cars, trains, and planes may not be possible.