Jeff has been in china for a year,so his parents have not seen him ___ last April.

题目

Jeff has been in china for a year,so his parents have not seen him ___ last April.
A from B for
C since D by
请问这道英语单选选哪个呢?
请告知为什么选那项,别的为什么不选?最后还请翻译一下这句话..

答案

C since
Jeff到中国已经一年了,所以他父母自从去年四月起就没见过他.

for表示一段时间,一般不能用于某个时间点；
by表示某个时间点之前,明显和句子意思不对；
from一般要跟to连用,表示一个时间段,意为“从……到……”.
since也表示时间段,意为“自从……”,常常用于完成时.