Question

（B C）26.They have known each other_____.(复选) A.from last year B.since 1976 C.for many years

D.only a few years ago
为什么是选B、C

Answer 1

主句中时态是现在完成时， have known ， 时间状语要注意了。
现在完成时态的标志词如下：since+时间, for + 时段, already（肯定）, yet（否定，疑问）, just, before, recently, recent years, these days/years, still, lately, in the past few years, ever since, in the last five months, up to now, since then, so far, ever, never, yet, twice, once, on several occasion, in the past few days/weeks/months/years, (up to)these few days/weeks/months/years, this morning/week/month/year, up to present, up to now,till now .....
该句中符合的是B.since 1976 C.for many years（Since，，，， 和 for。。。）

Answer 2

句子使用了现在完成时。能与现在完成时连用的时间状语有since+时间点， for +一段时间，

故选B/C

其余两个用于一般过去时