hello everyone welcome back i'm teacher sarah in today's video let's learn about modal verbs
so today let's talk about three modal verbs today we will look at the modal verbs
should ought or ought to and must these words are used in many different ways we can use these words
to talk about duty and obligation obligation is something that you have to do if you have
an obligation it means no choice you have to do it so we can use these words to talk about things we
have to do we can use these words to give advice and to say what we think is right for people to do
or about what people have done our opinion about what people have done if we think it is right
so let's take a look at the many different ways we can use these terms first let's look at
should and ought these two verbs are very similar and can often replace each other this
means most of the time if i use the word should i can also just replace it with the word ought
or ought to although in english should is used much more often than ought so if the word ought
confuses you or you don't use it very often that's okay you can use should in place of it
so let's take a look at some examples of how we can use should and ought to interchangeably or
some examples that show that we can use these words in just the same way first example
you should see star wars it's a great series
or you ought to see star wars it's a great series so here i'm telling you i think it's a good idea
for you to see star wars i think you should do it i think you ought to do it same meaning
here's another example you should join us you ought to join us so here i'm suggesting
or saying that um it's a good idea come on come on you should join us you ought to join us so we
can see in these two examples that we can use should and ought to in very much the same way
let's look at another way should and ought can be used should and ought are also used to talk about
logical probability uh what is logical probability this means something that is most likely true
if i think about it it's probably true so let's take a look at an example
i bought two pizzas that should be enough i bought two pizzas that ought to be enough
so let's say i'm having some friends over and i decide to order some pizzas i think
most definitely right really most probably that two pizzas will be enough for all of my friends
so i could say that should be enough or that ought to be enough
not quite the same as saying that is enough uh maybe right there's a tiny
tiny chance maybe we'll eat two pizzas and we still want more but
i look around and i think that should be enough that ought to be enough let's see another example
uh let's say i am waiting for my friend jack to come over and finally i hear a knock on the door
oh that should be jack knocking on the door or that ought to be jack knocking on the door so i
was expecting him if someone comes and knocks on my door it is most likely most probably jack right
i'm expecting him there's a small chance that maybe maybe it's the the post man uh or maybe
it's someone else but most probably it's jack ah that ought to be jack so here we see we can use
should and ought to talk about logical probability or something that is most most most likely true
okay next let's talk about the modal verb must must has similar meanings to should
and ought but is stronger and more definite so let's take a look at some examples
here's sentence number one the doctor said i must give up smoking
this is an order if your doctor says you must give up smoking it means you you
must you have no choice you are obligated to do it you have to do it it is in order you must
whereas if we use uh should or ought to here you know you really ought to give up smoking
this is just a suggestion or some advice it is not someone telling you what to do
it's just a suggestion so we can see that must is a much stronger word
let's see another example of how must is stronger than should an aunt if i say ada must be home now
that means i'm sure she's home maybe aydah is my daughter and i told her to be home by 7 pm
if it's 7 30 i could say aydah must be home now it means i'm sure she's home i told her to be there
she must be there this is very definite right i'm very positive very sure that she's there
maybe if it's only 6 30 or 6 45 though i could say aydah should be home now right i
think she's home she should be she might be but i'm not as sure so must is used when we are sure
or something is definite or it's in order so let's expand what we've talked about
so far are the most common and most simple and frequent use uses of these verbs so let's expand
and see some other maybe more challenging ways that we use these terms in english
should can be used instead of must to make orders and instructions more polite
this is very common for businesses when they are telling their customers to do something
or even when teachers are telling their students to do something they might use should instead
of must or have to to be more polite for example this form should be filled out in ink
okay well you really have to fill it out in ink or they'll make you do it again but by using the word
should it sounds more polite here's a similar example applications should be sent by may 31st
well you must send them by may 31st or it won't be accepted but to be more polite they should
be sent by may 31st so we can use should to make our instructions or orders a little more polite
here's another expansion for the words should and ought should and ought can be used for predictions
but not must so a prediction is when we are guessing what will happen right so for example
i could say the weather should be fine tomorrow or the weather ought to be fine tomorrow
i'm predicting i'm guessing weather is a little unpredictable maybe it will rain we don't know
we think we're sure but not totally positive so i could say the weather should be fine tomorrow
let's go camping the weather ought to be fine tomorrow let's go for a picnic but i cannot use
must i would not say the weather must be fine tomorrow because i can't tell the weather what
to do right i can't tell the future what to do so when we're talking about the future and making
predictions we can just use should and ought all right we have one more also about should and ought
as you see there are so many uses for these words uh this is the last one we'll talk about today
should and ought can be used to talk about unfulfilled obligations in the past so things that
didn't happen but you should have done in the past and again we cannot use must because it
has already happened so for example let's say um i'm talking to my friend she goes on a date with
a guy and it doesn't go well she tells me about it i might say hmm you should have been nicer to him
so i'm saying this is something you should have done in the past you should have been nicer to him
i think this is how you should have changed your behavior right you ought to have come
to the meeting so you really kind of needed to come to the meeting but you didn't maybe
you missed a lot of information oh you ought to have come to the meeting
right so here we can also use should and ought to talk about things that didn't happen in the past
that you should have done but again we cannot use must because must means it hasn't happened
yet right if i'm telling you to do something you must be nicer to him it means you ha it hasn't
happened yet it didn't happen in the past and i'm not predicting the future we can only use
must in that very particular way so be careful when you're using these kinds of sentences