问题补充:
By next summer John in this factory for thirteen years.
A. has been working
B. will have been working
C. will be working
D. has worked
答案:
A. has been working
(答案→)B. will have been working
C. will be working
D. has worked
解析:考察时态。本题的关键是by到…时为止;该词通常与完成时连用,本句后面的时间状语是next summer,这是一个将来时的时间状语,故本句使用将来完成时。句意:到今年夏天结束的时候,John将在这家工厂里工作了了。故B正确。