more careful the work might have been done better.A. BeingB. Having beenC. If you had be

问题补充：

more careful, the work might have been done better.

A. Being

B. Having been

C. If you had been

D. To have been

答案：

A. Being

B. Having been

(答案→)C. If you had been

D. To have been

解析：考查if 的过去虚拟句。 If 后用had done, 主句用情态动词+have done