前面可加冠词the或者a,例如:
1.This is the second time it's happened.这已是第二次了。
2.It was the second air disaster in the region in less than two months这已经是该地区不到两个月内的第二次空难了。
3.I'll be with you in a second.我马上就去你那儿。
4.I'd like a second opinion before I make a decision.我在作决定之前,想听听别人的意见。
如果是强调次序的话,用定冠词the ,如果是强调再一,又一,用不定冠词a