有时在交通高峰期被困足以使人发疯（stick/drive sb.mad)如何译?

有时在交通高峰期被困足以使人发疯（stick/drive sb.mad)如何译?
书上有两种译法：1.Sometimes it's enough to drive you mad if you are stuck in a traffic jam during the rush hour.
2.Being stuck in a traffic jam sometimes during rush hours can drive you mad.
可是,为什么第二种译法里“hour”后加“s”,而第一种没有?劳各位费神了,谢谢!