．How long is it we last spent the holiday in the country together?
A. until
B. before
C. since
D. that
网友回答
A. until
B. before
(答案→)C. since
D. that
解析：考查时间状语从句。Until直到；before在......之前；since 自从；that不能引导时间状语从句。句意：自从我们上次一起在乡村度假，已经多长时间了？Since+一般过去时态的句子，主句用一般现在时态或现在完成时态。所以选C。