_you have any difficulty in completing the experiment,ring this number.
问题描述：
_you have any difficulty in completing the experiment,ring this number.
A.wouldB.couldC.shouldD.might
正确答案是C,我选的是D,求高手解答为什么是should?
答
这里用should...倒装句,是虚拟语气,假如.的意思,相当于if you had any difficulty...