MIDI和MP3是PC机中两种不同类型的数字声音。下列叙述中，正确的是______。

A．MP3是一种经过压缩编码的符号声音

B．同一首乐曲的MP3文件比MIDI文件的数据量少

C．MIDI文件的后缀名是.wav

D．MIDI和MP3都可以使用Windows的媒体播放器进行播放

句型变化 

1.The question is so hard that we can't understand it.        

1) too...  to句式_____     

2) enough句式_               

2.He didn't come here yesterday because of the heavy rain. (变为复合句)          

He didn't come here yesterday _____.      

3.Get up early, or you'll be late for the train, (变为条件状语从句)          

_____, you won't be late for the  train.        

4.If you speak more,  you'll speak better. (同义句)       

____you speak,____you'll speak.        

5.Wherever you go, I'll miss you for ever. （同义句)         

    __you go, I'll miss you  for ever.