祈使句表达命令、要求、请求或劝告等功能。祈使句中的谓语为动词原形，无时态和数的变化，朗读时一般用降调，句末用句号或感叹号。

—Sorry, Joe. I didn't mean to…

—Don't call me "Joe". I'm Mr. Parker to you, and ______ you forget it!

            A. do            B. didn't                    C. did                  D. don't

一、含有第二人称主语的祈使句

1）第二人称主语通常不表示出来，其否定式则在句首加"Don't"，反意问句的附加部分一般是"will you?" 。  例如：

Be quiet!     Get him his change!      (SB.2A P57)

Check the prices before you decide whether to buy one. (SB.2A P67)

Take a deep breath and I'll time you. ( SB.2A P19)