问题补充：
---do you write a letter to your father?
--- I seldom or never do that now. Instead, I call or e-mail him almost every day.
A. How 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：你多久给你父亲写一封信？我很少或从不这样做。相反，我几乎每天都给他发电子邮件或打电话。How soon多久以后；How long多久；How much多少；How often多久一次。根据I seldom or never do that now.可知该选D.
