He more visits to his parents.He has been regretting not doing so since they passed away.

问题补充：

He more visits to his parents.He has been regretting not doing so since they passed away.

A. should pay

B. would pay

C. should have paid

D. would have paid

答案：

A. should pay

B. would pay

(答案→)C. should have paid

D. would have paid

解析：此题考查的是should have done结构。该结构表达与过去事实不相符的语气，意为“本应该……”，而事实上未能做到。should含有责备、批评的意味。