— do I have to change the robot’s batteries? —Every two months.A. How longB. How soonC. Ho

问题补充：

— do I have to change the robot’s batteries? —Every two months.

A. How long

B. How soon

C. How often

D. How many

答案：

A. How long

B. How soon

(答案→)C. How often

D. How many

解析：本题的回答语意思为每两个月，表示的是频率，对此提问应该用how often，故选C,how long对长度提问，how soon对多久以后提问，how many对可数名词数量提问。