Commands, and Negative Commands

In positive commands, we use the INFINITIVE VERB without "to"

and without SUBJECT:

·         Go!

·         Look at me.

·         Help!

·         Be quiet.

·         Be good.

·         Stop talking.

·         Sit down.

·         Shut up!

·         Call the police!

·         Wait a minute.

In negative commands, we use: "do" + "not" + INFINITIVE VERB

without "to" and without SUBJECT:

·         Don't wear that stupid hat.

·         Do not sign your name with a pencil. Sign with a pen.

·         Don't walk on the grass.

·         Don't act like an idiot.

·         Don't yell at me!

Of course there are many words to soften a command:

Please, excuse me, pardon me, thank you, thanks

·   Please repeat the question.

·    Please speak more slowly. --Thank you.

·    Tell me please, what time is it? --Thank you.

·    Excuse me, pass me the salt please. --Thanks

·    Excuse me, come this way please.

·    Pardon me, please don't smoke in the elevator.

·  Pardon me, please speak quietly, remember that you are in a hospital.

·         Hold on please.

source: http://www.easyenglish.com/lesson.asp?dont.txt