spend on和spend in的用法到底是怎样的?

题目

spend on和spend in的用法到底是怎样的?
以前我们初中老师讲spend说,spend money/time on sth.spend money(on)doing spend time (in) doing
意思就是说若在doing前加介词,money要用on,time要用in,但是高中里的老师却说不管money还是time都是spend (in) doing……所以我混乱了……

答案

很少见 spend time in doing sth 这种说法.
一般而言,spend time 后如果直接跟“动名词”（v+ing）,既不用 in 也不用 on.
如果后面跟的是地点状语,用 in；如果跟的是事或人,用 on.例：
My parents spent their vacation in Paris.
I spent all my resources on futile projects.
John spent most of his time on his girlfriend.