Recently we asked for your opinions about paying students to improve school attendance or performance on tests.Some American schools are doing this.请问performance 为什么不用复数performances?应该既是可数也是不可数uncountable and countable，请问什么时候是可数，请举例 英语
网友回答
【答案】 performance在上句中的意思为表现
performance作表现,能力,性能的意思时,是不可数名词,
当作表演的意思时,才是可数名词
Eg:The singer's performance was terrible.
There are two performances a day.