答案是wasting 或者to wasting
rather than do的结构一般只出现在:
would do rather than do,prefer to do rather than do
但是它常规的一个用法就是连词短语,也就是连接两个并列的成分,
原句可以调整为:
I devoted every effort to making an advertisement rather than (to)wasting time playing cards as usual.也就是说,
making an advertisement 和wasting time playing cards as usual是两个平行并列的短语
并且由rather than 连接.
例子:I want it on the desk rather than in the draw .
我想把它放在桌上而不是在抽屉里.on the desk 和in the draw 是平行结构
ps:本人感觉这个题太冗长,直接改成:
I devoted every effort to making an advertisement rather than playing cards as usual.
这样不是更简洁吗?