The new machine if properly will work at least ten years.A. useB. usingC. being usedD. us

问题补充：

The new machine，if properly，will work at least ten years.

A. use

B. using

C. being used

D. used

答案：

A. use

B. using

C. being used

(答案→)D. used

解析：本题考查分词与主语之间的关系。if the new machine is used properly…