We don’t write to each other regularly，but we do keep intouch by telephoning ___

题型：不详难度：来源：

We don’t write to each other regularly，but we do keep in
touch by telephoning _____.

A．at a time

B．once

C．at once

D．once in a while

答案

D

解析

once in a while“间或，偶尔”;at a time 每次，一次；once 一旦；at once 立刻，马上。题意为：我们不经常相互写信但我们偶尔会通电话。