15. A storm __________by a calm.
问题描述：
15. A storm __________by a calm.
A. is often being followed B. was often followed
C. is often followed D. has often been followed
这题为什么选择A?
答
be+(always,often等等表示频繁发生的副词)+doing 表示经常性发生的事情
A storm is often being followed by a calm
按字面翻译的话就是:平静总是跟在暴风雨之后