超声波是人耳听不见的声音，但它有着广泛的应用，在下列设备中，利用超声波工作的是（　　）

阅读理解

A

　　 Dolphins (海豚) are not fish but mammals (哺乳动物)．They live in groups, and speak to each other in their own language. In this way they are like many other animals, like bees. But dolphins are very different from almost all land animals. Their brain (脑) is nearly the same size as humans', so they are the cleverest animals. And they live for 20 to 30 years.

        But what does the dolphin look like？The dolphin has teeth, and eats fish. It can grow up to three and a half metres long. Its nose is very long. Like some other animals, the dolphin uses sound to find its way. They make sound to talk to each other and to help find food. We now know they don't use their ears to listen to the sound, but the jaws (颚)．

　　　Dolphins are friendly to people. They often save people in the sea. So many people like them.

阅读下面材料，在空白处填入适当的内容（1个单词，部分空格2个或者3个单词）或括号内单词的正确形式。将答案填写在答题纸相应位置。

    The British love sending text messages. They send more than 2.5 billion every month. And most people now understand the language of text, with its numbers and missing ____(letter), In fact, when a student at____Scottish school wrote the whole article “in txt”, his teacher give him “c+4 f4t” (“c + for effort”).

____texing is a cheap way of staying in touch with your friends, it can also bring problems. In 2005, a British teenager became ____ (one ) person in the world to receive treatment for an addiction(沉溺) to text messaging. In one year, the nineteen-year-old spent about £4,500

____texts.

    For some people, text messaging____(change) their lives already. For example, James Trusler from England travels around the world____(take) part in texting competitions and TV shows. He's the world's fastest texter and recently set a new world record while he was appearing on Australian TV. He texted: “The razor-toothed piranhas of the genera Serraslmus and Pygocentrus（脂鲤属和红肚属水虎鱼）are____(terrible) freshwater fish in the world. In reality they seldom attack a human. ” ____took him 67 seconds. James sends a lot of text messages-about 2,500 a month. But he doesn't get big bills____he works for a large mobile phone company!