Hi guys!
I hope you're doing well, because I'm pretty good myself!
We're back with a new video and this time we'll talk about the modal verb "must".
The subject pronouns and the infinitive form of verbs
that might come up in different way.
Let's begin with "must"!
This is a modal verb,
which means that it's an auxiliary verb
that brings a different meaning to the main verb.
In the affirmative form,
it is used to infer the idea of obligation.
Which means that there will be consequences if you do anything different than you must.
Does it make sense?
Well, maybe we should see some examples to make things clear.
Look,
this is an obligation because it's a law.
If don't respect the carpool lane rules, you may face consequences.
We've got the same situation here,
in the US the law says that overtaking on the left is mandatory.
Doing it otherwise is not only against the law,
but it might also cause accidents.
Now, pay attention to the structure.
Both sentences are in the affirmative form,
so we have the subject "you" then the modal verb "must",
the main verb and finally the complement.
As a matter of fact,
"must" is widely used when we refer to traffic rules,
safety regulations, laws and every other situation
that refers to obligations.
Let's see a few more examples!
So, we've seen that "must"
means something mandatory or obligatory
when used in the affirmative form.
But what does it mean in the negative form then?
The negative form of must
actually carries a completely different meaning.
"Mustn't" refers to prohibition, the things you are not allowed
or have no permission to do by any means.
You can say either "must not" or "mustn't".
However, as you may expect,
"mustn't" is more common in the spoken language
and it sounds more natural.
When you don't use the contracted form,
it sounds like you're emphasizing that information.
So without further ado, let's see how we can use "mustn't"
is a sentence, shall we?
We have the subject "you", then the contraction "mustn't",
and the main verb "speed".
Look at this other one.
Once again the subject is "you",
followed by the modal verb "mustn't", the main verb "drive",
and then the complement "on the shoulder of the highway".
Did you notice how we mentioned "you"
as the subject of every sentence in the affirmative and negative forms?
Well, that's because "you" is a subject pronoun.
Subject pronouns replace nouns that work as the subject of the sentence.
Let me show you what a subject is.
"Marco" is the subject in this sentence,
because he is the one who performs the action.
If we continued to talk about Marco,
it's best not to keep repeating his name.
In this sentence "he" refers to Marco,
and by using this pronoun we avoid repeating his name.
This is the main function of a pronoun, see?
Let's see the subject pronouns in English.
They are:
"He", "she" and "it" are the third person singular.
"He" is male, "She" is female, and "it" refers to a neutral gender.
And the plural form "they"
is the only third person.
Another important thing to note is that "you"
is used both for singular and plural.
Now you must be thinking,
how am I supposed to know the difference?
You'll know it based on the context, check it out!
In this sentence we're talking about "a" good driver.
There's the article "a",
which is only used with singular nouns.
And the noun "driver" is in the singular,
so it's clear that we're talking to only one person.
Now, see another example.
"Good drivers" is in the plural form,
so we're referring to more than one person.
speakers of the language will help you see this difference in their speech
by using a word along with a pronoun.
They may say "you people" or "you guys",
to make it clear that it refers to more than one person.
For example:
In this sentence, you'd only know by context,
as "you" doesn't make it clear whether is one or more.
This is different.
"You people" emphasizes the plural form,
and this is a way to avoid misunderstandings.
And there's another possibility.
"You" is the second person singular, or plural.
And now that you know that,
let's take a look at the third person singular.
"He", "she" and "it".
"He" for men, "she" for girls.
For all other cases use "it".
Let's see some examples!
As you can see, we first mention the person's name,
Arthur.
And on the next sentence we use "he" to refer to him,
as Arthur is a male name.
Check another example!
See the difference? In the previous example we had a person,
so we used "he".
Here we have a car, so we use "it" to make the reference.
Another one!
As Julia is a female name, we use "she" to refer to her.
We use "it" again because we're referring to street,
which is a noun.
See, guys?
Not that hard! Pretty simple to understand, right?
There's another situation in which we use "it",
in a function called "impersonal it".
And why is that?
When "it" is used in this function,
it's not replacing a noun such as "car" or "streets".
It's simply being used as the subject of the sentence,
because most affirmative sentences in English must have a subject.
Take a look!
We can't replace "it" by a noun in this sentence,
"it" is impersonal,
and it simply works as the subject of the sentence.
The same thing here:
And remember guys,
it's not possible to replace "it" by a noun in these sentences.
But we cannot take it out either,
it's incorrect to say "is prohibited to litter" or "is illegal to drink and drive".
Well,
but there were other verbs besides the ones with the subject, right?
Here we have the verb "to be", "is",
following the subject "it".
Then we have the verb "to litter",
and its infinitive form as the complement.
Here we also have the verb "to be", "is",
followed by a complement "to drink and drive".
Note that the verb "to litter" comes right after an adjective.
"Prohibited" just like the complement "to drink and drive",
follows the adjective "illegal".
Well guys,
this is a pretty common structure in English, right?
Adjective + infinitive.
And do you know what the infinitive form is?
The infinitive form in English
is marked by the use of the preposition "to" before the verb.
This preposition has no particular meaning in this use,
all is does is indicate the infinitive form of the verb.
So, this is what we have:
The preposition "to" is placed before the verbs
to indicate their infinitive form.
They may also be in sentences,
like when you want to make a comment on a certain action.
Here's the adjective "illegal" and the verb "to smoke",
which is a verb in the infinitive form.
Let's see a couple more examples.
Well guys, this is it for now!
We've studied how to use "must" to express obligation,
"mustn't" to express prohibition, the subject pronouns,
and the structure adjectives + infinitives.
And you do know what you must do now, right?
That's right, do the exercises to practice more!
I'll see you on the next video, have a good one!