Prepositions of time | The parts of speech | Grammar | Khan Academy Video Lecture | Complete Course on English Grammar: Upgrade your Speaking & Listening - Personal Skills

hello grammarians we are once again
learning how to master time and become
time wizards which is of course what you
will be if you master all the tenses of
English but if you want to become an
additional time wizard if you want to
get I don't know second hat everyone
owes all Wizards where multiple
simultaneous hats if you want to wear a
second hat on top of your other time
wizard hat as the silliest thing I've
ever said
then you will have to learn the
prepositions of time now here's
something weird and cool about
prepositions of time is that once upon a
time all of these were physical
prepositions like before and after just
used to mean behind and in front of you
know then they later took on this
additional connotation of time just over
the course of english-speaking history
people took this literal meaning of you
know before and after and made it
representational you know this moment
occurred in front of this one in time
but behind this other one in time it's a
metaphor we're using space to represent
time anyway I just thought that was
really cool let's talk about how all of
these work I'm just going to list a
couple of the most most famous
prepositions of time and write an
example sentence so let's go through
these after and before as we've
established these these are time
relationships that you know refer to
something happening after so when
something is completed say the bats come
out after the Sun Goes Down and before
this occurs prior to some point in time
so it is behind in action so you can say
can you take out the garbage before you
leave the house at is very precise when
we're talking about at we're talking
about a single moment in time we could
say the vampire wakes at 10 p.m.
there is emerging from his coffin
that is the his oh that's not the Sun
the Sun would burn a vampire no that's a
um it's his a little clock it's got a
tail it's like a little wacky cat clock
no that clock and then seven that
doesn't have a tail it's got little
stubby tail do I really want a bat clock
now anyway okay bye this this is a
really precise end time but not a very
precise beginning time so you could say
something like this place had better be
clean by 3:00 p.m. buddy
and if you say something like that
you're not especially concerned that the
place might be clean before 3:00 that
would be nice but it's only relevant to
you that the cutoff time is at 3:00
o'clock so the end is precise that's the
connotation there but the beginning is
not for denotes duration how long
something has been going on so you could
say I've been a chef for 40 years I
haven't but that would be cool and
difficult but you know what this is Khan
Academy you can cook anything in denotes
a bounded duration so it's something
that lasts for a specific amount of time
like a limited period okay so let's say
bounded duration so that covers usage
like you know in March or in the Middle
Ages both of both of those things are
like set periods March has a beginning
and an end the middle ages have a
beginning and an end it's a it's a
bounded duration on has a specific
connotation it's something that happens
on a specific day you could say
something like on the fourth of July
many Americans watch fireworks and eat
encased meats mind you not everybody
eats hot dogs or likes fireworks so I
said many not whole
since is kind of like bi except it's
more about the precision of the start
point rather than the end point so
precise beginning since 1974 our company
has made nothing but toasters until is
also precise but its precise ending time
you have until midnight to rescue the
ambassador break the curse and save
prince Wilbur right so there's a precise
ending there you have until midnight and
then you can't rescue the the Ambassador
or break the curse or save any princes
but what you can do is learn anything
these are some of the most essential
time prepositions David out