用for或since填空：（1）Mr Li has taught in the school______he graduated from the college.
问题描述：
用for或since填空：（1）Mr Li has taught in the school______he graduated from the college.
(2)The old woman has waited for you_____five hours.
(3)The meeting has been on_____several minutes.
(4)The couple have been married_____1999.
答
(1)since
(2)for
(3)for
(4)since