custom作为风俗是可数吗

　　This particular custom has its origins in Wales.

　　这一特殊风俗起源于威尔士。

　　It was his custom to approach every problem cautiously.

　　谨慎地处理每个问题是他的习惯。

　　The custom of lighting the Olympic flame goes back centuries.

　　点燃奥运圣火的风俗可追溯到几个世纪前。