句意：当他又时间的时候,他喜欢玩电脑游戏,在网上冲浪,和听音乐.
这个句子应该是条件状语从句,when he has time是从句,主语是he,谓语是has,宾语是time,when相当于介词,的时候.
he enjoys playing computer games,surf the Interent and listening to music.
这句是主句,主语是he,谓语是enjoys,宾语是playing computer games,surf the Interent and listening to music三个并列的成分.并且,这三个其实是宾补结构,也就是说,computer games,the Interent,music是宾语补足语.
高中毕业后没再搞过这方面的东西,不知道解释的对不对,希望对你有点帮助.