do you visit your grandparents? -------Once a month.AHow soonB. How longC. How m

问题补充：

----- do you visit your grandparents?

-------Once a month.

AHow soon

B. How long

C. How much

D. How often

答案：

A. How soon

B. How long

C. How much

(答案→)D. How often

解析：句意： 你多久去看一次你的祖父母？每月一次。How soon多久以后； How long 多久； How much 多少； How often多久一次。根据答语once a month可知该选D。