Our job is playing all kinds of music . ( 动名词 )

　　The music they are playing sounds so exciting . ( 现在分词 )

　　注：一般来讲，动名词 ( 短语 ) 作表语，主表可互换，即：Playing all kinds of music is our job.

　　现在分词作表语，表明主语的性质和特征，主表不可互换。

　　2. - ing形式做定语可以表示

　　1 ) 所修饰名词的用途

　　a waiting room ( = a room for waiting ) / a walking stick ( = a stick for walking )

　　2 ) 所修饰名词正在进行的动作，可以换成定语从句形式

　　a waiting man ( = a man who is waiting ) / a sleeping child ( = a child who is sleeping )

　　3. 在see , hear , feel , watch , notice等感观动词后可以用 - ing形式做宾语补足语。这时 - ing形式和句子的宾语之间存在着逻辑上的主谓关系，并且 - ing形式表示宾语正在进行的动作。如：

　　He saw a girl getting on the tractor. ( = He saw a girl and the girl was getting on the tractor . )

　　Do you hear someone knocking at the door?

　　1).做宾语补足语We watched three boys sharing their food with each other.

　　2).做主语补足语She was heard singing in the next room.

　　3).做表语和定语My job is teaching English. /a walking stick/a waiting room

　　当-ing分词做定语的时候，常常放在被修饰名词的后面

　　The girl singing now is a classmate of mine.

　　4).做伴随、原因、时间、结果状语

　　He sat at the desk reading a magazine.

　　Being very young, he can't dress himself.

　　Having finished all the work, they went to the shore.

　　Her parents died, leaving her a big house.