for 和since
问题描述：
for 和since
for 后面跟时间段,而since加时间点.刚才做题是这样的.my uncle went to china last year,we have not seen him
A for almost a year b from almost a year on c from almost a year d since almost a year ago答案为啥是D啊.
答
since+过去某一时间或句子,for+一段时间
She has taught in the school for ten years.她在这所学校教书已经10年了.
I haven't eaten anything since breakfast.我从早饭起就一直没有吃东西.