1

Unit
31 must mustn't don't need to
m ust + in fin it ive (m ust do / m ust w ork etc.):
do
It ’s a fa n t a st ic film.
You m ust see it.
l/ w e/ you/ they
he/ she/ it
m ust
go
see
eat
etc.
.; ............. .... ......... .
I m ust (d o so m ething) = I need to do it:
O
I'm very hungry. I m ust eat som ething.
O
It's a fantastic film . You m ust see it.
O The w ind o w s are very dirty. W e m ust clean them .
For the past (yesterday / last week etc.), w e use had to ... (n o t m ust):
O I was very hungry. I had to eat som ething. (n o t I m ust eat)
O W e had to w alk hom e last night. There were no buses. (n o t W e m ust w alk)
m ustn't (= m ust no t)
I m ustn't (d o so m ething ) = it is necessary n o t to do it,
it is the wrong thing to do:
O I m ust go. I m ustn't be late.
O
I m ustn't forget to phone Chris.
(= I m ust rem em ber to phone her)
O Be happy! You m ustn't be sad. (= don't be sad)
O You m ustn't touch the pictures.
(= don't touch the pictures)
You m u stn ’t tou ch
t h e p ictu res.
don't need to
I don't need (to do so m ething ) = it is not necessary:
O I don't need to go yet. I can stay a little longer.
O You don't need to shout. I can hear you O K.
You can also say don't have to ...
O I don't have to go yet. I can stay a little longer.
Co m p are don't need to and m ustn't:
O You don't need to go. You can stay here if you want.
O You m ustn't go. You m ust stay here.
72 ( I have to ... Unit 33