custom（风俗,习惯）是不可数名词。
例句：
The custom dates back hundreds of years.
这一习俗可以追溯到几百年前。
As was his custom, he knocked three times.
他敲了三下，这是他的习惯。
扩展资料
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。
