He﹍﹍the job well, but he so careless.
A. had done; had been
B. could do; was
C. could have done; was
D. hadn’t done; had been
网友回答
A. had done; had been
B. could do; was
(答案→)C. could have done; was
D. hadn’t done; had been
解析：这题考查虚拟语气，句意是：他本可以做得很好，但是他太粗心了。粗心是过去的事实，工作做得好的虚拟的用法，实际上并不好。所以第一空填could have done“本可以做却没做”，第二空填was，是过去的事实。选C