spend是什么时态

　　Stores spend more and more on crime prevention every year.

　　商店每年在防止犯罪方面的花费越来越多。

　　Poor families spend about 80 to 90 per cent of their income on food.

　　贫困家庭大约花费收入的80%到90%购买食物。

　　I spent what little time I had with my family.

　　我仅有的一点儿时间都和家人在一起度过了。

　　The money could be better spent on more urgent cases.

　　这笔钱用于较紧迫的事情也许会好些。

　　I spent most time on the first question.

　　我在第一个问题上花的时间最多。