Study materials
Instructions in a recipe, on a sign or from a friend are short. The sentence simply starts with the action.
Add two eggs.
Don't feed the animals.
Let's go home!
This article explains how the imperative is formed, how to say don't do it, where please, never and always go, and how to invite someone to do something together with let's.
How the imperative is formed
The verb form for instructions, advice and requests is called the imperative. The sentence starts straight with the action, the verb in its base form, the way it appears in a dictionary. The subject, the one who does the action, is not named. The word you is left out, because it is clear who is being spoken to.
Turn left at the bank.
Go straight on, then turn right.
Call me tonight.
The form is the same for one person and for several. It never takes an s ending or to.
Opens the door. → Open the door.
An instruction has no he or she, so no s.
The same form is used for good wishes.
Have a great holiday!
Enjoy your meal!
The word please softens an instruction and can go at the start or at the end. Never and always go at the very start, before the verb.
Please sit down. Sit down, please.
Always wear your seat belt.
Never open the door to strangers.
Never already means not ever, so don't is not added to it.
Bans and be
A ban is built with don't and the base form, the same for everyone. Please can even go before a ban. Signs often use the full form do not, which sounds stricter.
Don't touch the cake.
Please don't shout.
Do not touch.
A sign in a museum.
If the instruction has a description rather than an action, it needs the verb be. Be stays in its base form too, so it is be, not are or is.
Be careful!
Don't nervous! → Don't be nervous!
The most polite of all is not an instruction but a question with Can you and please: Can you close the door, please?
Let's
When you invite someone to do something together with you, use let's. Let's is also followed by the base form with no to. Let's is short for let us, so we does not follow it.
Let's order pizza!
Let's not wait.
To suggest not doing something, add not after let's. To agree, say simply Yes, let's.
Let's watch a film! Yes, let's.
Common mistakes
The first mistake is to after don't.
Don't to forget your keys! → Don't forget your keys!
The base form follows don't.
The second mistake is an s ending.
Opens the window, please. → Open the window, please.
The imperative has no s.
The third mistake is a missing be.
Don't late tomorrow! → Don't be late tomorrow!
Late describes, it is not an action.
The first mistake shows after don't. The bare base form goes there, with no to. The second shows at the end of the verb. An instruction has no he or she, so it needs no s. The third shows when an adjective, a describing word like nervous or late, follows don't. Then be is missing between them.