miércoles, 29 de marzo de 2017

HAVE TO, MUST, OUGHT TO, NEED & SHOULD



Modal Verbs of Obligation

We can use have to + infinitive, must + infinitive and should + infinitive to express obligation (something you have to do).
PresentPositiveNegative
have to /
don’t have to
strong obligation (possibly from outside)
  • Children have to go to school.
(sometimes ‘have got to’)
no obligation
  • I don’t have to work on Sundays.

  • You don’t have to eat anything you don’t like.
must / mustn’t strong obligation (possibly based on the speaker’s opinion)
  • I must study today.
negative obligation
  • You mustn’t smoke here.
should / shouldn’t mild obligation or advice
  • You should save some money.
mild negative obligation or advice
  • You shouldn’t smoke so much.
Be careful about the difference between mustn't and don't have to!
Mustn't
means it's not allowed, or it's a bad idea:
  • You mustn't eat so much chocolate, you'll be sick
Don't have to means you don't need to do something, but it's fine if you want to do it:
  • I don't have to get up early at the weekend
    (of course, if I want to get up early, that's fine, but I can stay in bed if I want
PastPositiveNegative
had to / didn’t have to obligation in the past
  • I had to go to wear a school uniform when I was a child.
no obligation in the past
  • We didn’t have to go to school on Saturdays.
must*changes to 'had to'-
should have + pp / shouldn’t have + pp a past action which didn’t happen: the advice / regret is too late
  • You should have gone to bed earlier, now you have missed the train.
a past action which didn’t happen: the advice / regret is too late
  • You shouldn’t have taken that job., it was a bad idea.

* Remember ‘must have done’ is a modal verb of deduction or speculation, not obligation in the past. For example: Julie must have left. Her coat’s not here.



EXERCISE ONE
EXERCISE TWO
EXERCISE THREE
 

Should, Ought to BY WWW.ECENGLISH.COM

For giving advice or expressing a conclusion 'should' and 'ought to' are interchangeable. They are used to express the same ideas.
You should/ought to stop smoking. He has been working on the project all week. He should/ought to be ready by this evening.
Should is also used in hypothetical situations: Should anyone call, take a message.
Call me should you need any help.

Should is used with 'imagine', 'say' and 'think' to give a tentative opinion: I should think it will take us an hour to drive to Rome.

Need

'Need' expresses necessity: You need to exercise more often. You're putting on weight.
You don't need to wear a tie if you don't want to.

Needn't have/Didn't need to

'Needn't have' is used to talk about an action that was done but was unnecessary. We needn't have rushed to the airport. The flight was delayed.
I needn't have brought an umbrella. It didn't rain.

‘Didn't need to' is used to talk about an action that wasn’t done because it was not necessary. I didn't need to call Mike. I met him in the street.

EXERCISE ONE
EXERCISE TWO 
EXERCISE THREE 

jueves, 23 de marzo de 2017

PAST PERFECT.



Using the Past Perfect 

by www.perfect-english-grammar.com


Past Perfect Infographic 
 
 
1: A finished action before a second point in the past.
  • When we arrived, the film had started (= first the film started, then we arrived).
We usually use the past perfect to make it clear which action happened first. Maybe we are already talking about something in the past and we want to mention something else that is further back in time. This is often used to explain or give a reason for something in the past.
  • I'd eaten dinner so I wasn't hungry.
  • It had snowed in the night, so the bus didn't arrive.
If it's clear which action happened first (if we use the words 'before' or 'after', for example), the past perfect is optional.
  • The film started before we arrived / the film had started before we arrived.
2: Something that started in the past and continued up to another action or time in the past. The past perfect tells us 'how long', just like the present perfect, but this time the action continues up to a point in the past rather than the present. Usually we use 'for + time'. We can also use the past perfect continuous here, so we most often use the past perfect simple with stative verbs.
  • When he graduated, he had been in London for six years. (= He arrived in London six years before he graduated and lived there until he graduated, or even longer.)
  • On the 20th of July, I'd worked here for three months.
3: To talk about unreal or imaginary things in the past. In the same way that we use the past simple to talk about unreal or imaginary things in the present, we use the past perfect (one step back in time) to talk about unreal things in the past. This is common in the 3rd conditional and after ´WISH´.
  • If I had known you were ill, I would have visited you.
  • She would have passed the exam if she had studied harder.
  • I wish I hadn't gone to bed so late!