问题补充：
—Jack fell off the ladder yesterday，but he is all right now.
—What a lucky dog! He himself badly.
A. should injure
B. might injure
C. should have injured
D. could have injured
答案：
A. should injure
B. might injure
C. should have injured
(答案→)D. could have injured
解析：考查情态动词的完成式的用法。句意：——昨天杰克从自行车上掉下来了，但现在没事了。——真幸运！他可能会受伤的。由语境可知，空格处表示对过去情况的推测，应该在CD里面选择，could have done 意为“可能会…却没有”；should have done 意为“过去”应该干某事而没有干”。故D 项正确，
