My kitten got lost again yesterday. I ______ never have let it g

My kitten got lost again yesterday. I ______ never have let it go by itself.
A、might
B、should
C、would
D、could
【正确答案】：B
【题目解析】：本题主要考查的知识点为虚拟语气。 [要点透析] I should never have...表示“我本不应该……，却……”，有自责、惋惜之意。