20．Read the passage and fill in the blanks with proper words （在短文的空格內(nèi)填入適當?shù)脑~，使其內(nèi)容通順，每空格限填一詞，首字母已給）
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 MP3player．Some pop groups find that m（69）ore people listen to their songs on their mobile phones than they do on CDs．
Ringtones（鈴聲） are often used to tell you it's your phone．Companies s（70）ell them to you and they are downloaded on your phone．
At first，there were just different rings．They were like a normal（普通） telephone．Then people made them sound like a piece of music．Now you can get all kinds of sounds．N（71）early every pop song can be played on your mobile phone．You can also get a（72）nimal sounds-there are cats，dogs，tigers and lots of bird sounds，too．
You can make your o（73）wn music．You need special software to do it．Your voice 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 address book is used to find out w（74）ho is calling．Then it plays a different song for each person．If your best friend likes a special song，he can hear it，too!
You have to be c（75）arefully with the song you choose．Some songs can cause trouble．If your family call you，they don't want to hear a noisy pop song!You should choose something that sounds nice．
