例句：
He described the difficulties of surviving for four months as a captive.
他描述了被俘4个月里挣扎求生的艰难岁月。
The election was held six months ahead of schedule.
选举提前了6个月举行。
The area has been the scene of fierce fighting for three months.
这一地区3个月以来不断发生激战。
