Question

—_______ do you surf the Internet ?
—Once a month.

A．How soon

B．How old

C．How often

D．How long

Answer 1

C

根據Once a month，可知是詢問頻率。How soon是多久之后會發生某事；How old問年齡多大；How often 多久一次，回答頻率；How long多長。所以選C。