Asurveyhasshownthat40%ofthosekilledintrafficaccidents

问题详情：

 A survey has shown that 40% of those killed in traffic accidents _________ if they had been wearing seat belts.

A. should have been saved                                  B. must have been saved             

C. need have been saved                                     D. could have been saved

【回答】

D

知识点：虚拟语气与情态动词

题型：选择题