generation gap是可数名词还是不可数

可数的……
有关的例句有：a gap in the market, ie absence of a type of article which people might wish to buy 市场上某货物的脱销.
There were some unaccountable gaps in (ie parts missing from) his story. 他讲的话有些地方连贯不起来.

(不好意思啊，刚说的不可数是我自己理解错的。查了字典才改回来的)

年龄差异 the difference of/in the age