(·浙江金华二模)A survey has shown that 40% of those killed in traffic accidents if they had

问题补充：

(·浙江金华二模)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

答案：

A. should have been saved

B. must have been saved

C. need have been saved

(答案→)D. could have been saved

解析：选D句意：一项调查表明，在交通事故中丧生的人，如果当时一直系着安全带，那么他们中40%的人有可能不会丧命。根据“if they had been wearing”可知，此处是对过去情况的虚拟，主句谓语的形式应为“would/could/might/should＋have done”，排除B、C两项，根据句意应表示“可能”而不是“应该”，故选D。