spend的主语必须是人，常用于以下结构：

1、spend time ／money on sth. 在……上花费时间（金钱）.
例：I spent two hours on this maths problem. 这道数学题花了我两个小时.

2、spend time ／money (in) doing sth. 花费时间（金钱）做某事.
例：They spent two years (in) building this bridge. 造这座桥花了他们两年时间.

3、spend money for sth. 花钱买…….
例：His money was spent for books. 他的钱用来买书了.