问题补充：
If youto her about it yesterday, you what to do now.
A. should have spoken; would know
B. spoke; would know
C. had spoken; would have known
D. had spoken; would know
答案：
A. should have spoken; would know
B. spoke; would know
C. had spoken; would have known
(答案→)D. had spoken; would know
解析：考查虚拟语气。if虚拟条件句，对现在进行虚拟，从句用过去时（be动词用were），主句用would+动词原形；对过去进行虚拟，从句用过去完成时，主句用would/could have done；对将来进行虚拟，从句用过去时或should/were to+动词原形，主句用would+动词原形。根据now可知，if从句是对过去进行虚拟，从句用过去完成时，主句含有now，是对现在进行虚拟，用would+动词原形。这是错综虚拟条件句，要分别对主句、从句进行判断，分别使用对应的时态。故选D。
