-- do you see your grandmother ?-Once a month.A. How muchB. How longC. How soon

问题补充：

----- do you see your grandmother ? ------ Once a month.

A. How much

B. How long

C. How soon

D. How often

答案：

A. How much

B. How long

C. How soon

(答案→)D. How often

解析：句意：你多久看一次你奶奶？一月一次。根据答语可知，本空是问频率的，故用how often。所以本题选D。