---Why don’t you use the knife?-It needs .A. sharpenB. being sharpenedC. sharpeningD. t

问题补充：

---Why don’t you use the knife?

---It needs .

A. sharpen

B. being sharpened

C. sharpening

D. to sharpen

答案：

A. sharpen

B. being sharpened

(答案→)C. sharpening

D. to sharpen

解析：考查need doing需要被…=need to be done,句意是：为什么不用小刀？--需要磨锋利了。选C。