--- 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
网友回答
A. should injure
B. might injure
C. should have injured
(答案→)D. could have injured
解析：句意杰克昨天从梯子上掉下来了，但是现在好了。--真幸运！他本来会受伤严重的。因为是说明过去的事情，所以排除AB， --could have done 表示“本来可能而实际未……”。Should have done过去本应该做而没有做，根据句意应选 D。