Today’s trumpet is one of the world’s oldest instruments. It is really the result of many centuries of development. Al though it looks nothing like its ancestors, there are many similarities. All trumpets are hollow tubes. They are all blown. And they all use the player’s lips to produce the basic sound. The trumpet developed as players and makers worked to improve its design, size, shape, material, and method of construction. They wanted to create an instrument that would produce a beautiful and attractive tone, enable the performer to play all the notes of scale, extend the range higher and lower, make it possible to play more beautiful music, and, in general, be easier to play well. The remarkable way in which the modem trumpet achieves these goals is a measure of the success of all those who struggled to perfect this glorious instrument. The trumpet is actually the leading member of an entire family of related instruments. There are trumpets of several different sizes, and in several different keys. There are comets(短号), bugles, flugelhorns, and a number of others that are all similar to the trumpet in the way they are made and played. The trumpet family is much than a group of related instruments that can stir one with their sound, or narrow tubes of metal capable of producing a variety of musical sounds. It is a link to many different periods of history and to people of many cultures. From the use of trumpets in ancient religious ceremonies to the part they play in modem rock bands, the trumpet family of instruments has much to tell about civilization and its development. It can be inferred from the passage that which of the following is needed to make the trumpet work?