I''m surprised that he to help me when I needed his help .
A. should refuse
B. would have refused
C. should have refused to
D. may have refused
网友回答
A. should refuse
B. would have refused
(答案→)C. should have refused to
D. may have refused
解析：should 可用于表示惊讶、不快、忧虑等感情色彩的句子中。如指过去的动作，则用“should +不定式的完成式”，而 may 和 would 一般不带感情色彩。