Hello, guys! What's going on?
In the situational video and the interaction guide,
you learned some details about safety procedures before returning home.
Now, let's talk about some structures you can use
when you want to give commands,
ask for favors, or request permission.
A very frequent way to give commands or instructions
is to use the imperative form.
In this case, the subject is always "you".
That's why it's typically omitted from the sentence.
So, to use the affirmative form of the imperative
you just need the verb in its base form and a complement!
Look at this sentence to help you remember!
See? The subject does not appear in the sentence!
We just use the verb "take off" in its base form,
and the complement "your shoes".
Another one!
Here, we use the verb "place" in the imperative form.
And a third one:
Again, we have the verb "step" and the complement
"into the body scan".
Notice that we added "please" to this sentence,
which gives a nicer tone to this request.
But how do we use one of these sentences in the negative form?
In this case, we need "don't" + verb + complement,
this is the negative structure of the imperative.
Let's see an example to make it clear.
See that? We placed "don't" before the verb "step"
and added the complement "into the body scanner".
Now, pay attention to the use of "don't" in this structure.
The auxiliary verb in the negative form of the imperative is "do",
followed by "not".
The contracted form is "don't".
Remember that "do" as an auxiliary verb does not have the same meaning
as when it's used as the main verb of a sentence.
Check this example.
Here, we have the imperative form and "do" is the main verb.
Now, take a look at the negative form:
Here, "do" is also the main verb,
"do the research", but besides the main verb,
we also have the negative auxiliary verb, so, we have the "don't do" structure.
And it's all right!
The important thing is to understand that "don't" means denial,
and it doesn't have the same meaning of the main verb.
Let's see another sentence in the negative, but now with another main verb!
Now, we have "don't pack",
"don't" is the auxiliary verb and "pack" is the main verb.
Now that we saw the difference between "do" as a main verb and as an auxiliary verb,
I'll ask you another question, do you remember the simple present?
So, the verb "do" is the auxiliary verb of the simple present,
and it'll always show up in interrogative and negative forms.
In the affirmative structure, we have subject + verb + complement, right?
And when we want to form the interrogative and negative sentences,
we need to add "do" as an auxiliary verb.
We use "do" for "I", "you", "we", "they".
And in the third person singular we use "does" for "he", "she" and "it".
But you might be thinking, "how about the verb "to be"?"
Why does the present tense of "to be" not follow the same rules
as the simple present with other verbs?
I will tell you why!
That's because "to be" is the most irregular verb in English!
So, it follows a different structure from the other verbs in the simple present.
The verb "to be" is the only verb that never uses
"do" and "does" auxiliary verbs to form the simple present.
Check this out!
In the affirmative form we'll use "I am", "You are", "He, She, It is",
"We, You, They are", for example:
In the negative form, all we need to do is to add "not" after the verb "to be".
Look!
Note that we can contract "is + not" to become "isn't",
and "are + not" to become "aren't".
When the subject is "I", we can contract "I + am" to become "I'm".
Now, pay attention to one thing,
we can contract "I + am" to become "I'm", as I've mentioned,
but we don't contract "am + not".
Well, to be honest, this contract form exists,
and you might hear it as "ain't".
You may have already heard it in songs, movies,
or even in spoken English on the streets of the US.
But it is really informal, and you won't see it in a more formal situation.
So, it's important to understand it, but it's best not to use it.
Well, back to the verb "to be" structure,
we have seen the affirmative and negative forms,
what about the interrogative form?
There's no mystery, just invert the position of the verb "to be" and the subject.
So, it works like this:
For example:
You noticed that we didn't use "do" or "does" in any sentence
with the verb "to be" in the simple present, right?
Now, what if we use the verb "to be" in the imperative form?
What will the sentence look like? Do we use "don't" as an auxiliary?
Yes! Yes, we do! Check it out!
Here we would have to apply the general rule of the imperative form,
and use don't in the negative form even if the main verb is "to be"
In the affirmative, we'll follow the rule of the imperative form,
that is, no explicit subject in the sentence
and the verb in its base form, that is, "be".
Take a look!
The verb "to be" will be used in its base form
in many different structures,
for instance, while using "to be" with some modal verb.
Let me show an example with the modal verb "may"!
Here, we used subject + "may" + verb "to be",
following the same structure of other verbs with modal verbs.
That is, the verb after the modal verb is used in its base form.
And with "to be", it's no different.
You might be wondering,
why are you talking about "may" here?
Well, we often use the imperative to give commands, right?
But it's also common to use "may" to ask for permission
with the interrogative form "may I?".
And to give permission with the affirmative form, "You may".
Take a look at this example!
This is a sentence you may hear from the officer at the security check.
That means you are allowed to step out of the scanner.
The officer is giving you permission to do so.
Note that the structure of the sentence follows the structure of the modal verbs.
That is, subject + "may" + main verb + complement.
Pay attention to the context,
even though we use "you may" to ask for and to give permission,
depending on the situation or who you're talking to,
permission can be understood as an order.
Or maybe a polite way to give you and order,
as when the officer talks to you.
And it's correct to use the imperative.
Look!
But when we choose to say "you may step out", it sounds nicer.
Now, there's also another way to soften up the tone,
by using please in the sentence.
Of course, your tone of voice and intonation will also take part in this.
But, "please" is a keyword! Right, guys?
For example:
Here, when we add "please" to the sentence in the imperative, it sounds nicer,
and softens up the idea that this is a command.
Have you noticed how versatile the imperative form is?
That's it for now!
Don't forget to do the follow up activities and I will see you guys next time!
Bye!