Dad my trousers are old. I want to buy a new . A. trousers B. one C. it D. pair

问题补充：

Dad, my trousers are old. I want to buy a new .

A. trousers

B. one

C. it

D. pair

答案：

A. trousers

B. one

C. it

(答案→)D. pair

解析：本题的含义是我的裤子旧了，我想买新的一条，pair表示条的意思，故本题选D。