Tom is expecting a pet for long but his daddy has no time to buy for him.A. itB. oneC. t

问题补充：

Tom is expecting a pet for long, but his daddy has no time to buy for him.

A. it

B. one

C. this

D. that

答案：

A. it

(答案→)B. one

C. this

D. that

解析：one 代替上文提到的事物中不确定的一个，故选B