------ I wonder you’ll water this kind of tree.
------- Once a week.
A. how often
B. how long
C. how soon
D. how much
网友回答
(答案→)A. how often
B. how long
C. how soon
D. how much
解析：疑问词辨析。how often多久一次；how long多长；how soon多久；how much多少钱。根据下文once a week一周一次，可知上文提问频率，故选A。