First there were CDs, then we had MP3 music and now we have ringtones (铃声)! People use their mobile phones to play music. You can listen to the radio on your mobile phone, download music onto it and use it like a MP3 player. Some pop groups find that        people listen to their songs on their mobile phones than they do on CDs.
So many people have mobile phones that          you don’t know when your phone rings. Ringtones are often       to tell you it’s your phone. Companies sell them to you and they are downloaded on your phone.
At first, there were just different rings. They were like a normal telephone. Then people made the sound like a piece of music. Now you can get all kinds of sounds.          every pop song can be played on your mobile phone. You can also get animal sounds --there are elephants, cats, dogs, lions and lots of strange bird sounds, too.
You can make your          music. You need special software to do it. There are also karaoke ringtones. Your          is recorded with some music and you hear it when someone calls.
Now you can have a different sound for every person you know. Your           book is used to find out who is calling. Then it            a different song for each person. If your best friend likes a special song, he can hear it, too!
You have to be         with the song you choose, though. Some songs can cause trouble. If your family call you, they don’t want to hear a noisy pop song with        words! You should choose something that sounds nice. Some sounds are very noisy and fast, which make people angry. Ringtones are fun, but they should not make people angry at you!