Quando se estuda gramática, tem que se ter presente o fato de que não é apenas a forma (form) que se deve considerar como objeto de estudo. É preciso sempre lembrar que essa forma deve ter significado (meaning). Além da forma e significado, é preciso considerar também o uso (use).
Vamos recordar o sistema verbal da língua inglesa e como ele se comporta na formação das sentenças, tendo sempre a ideia acima em mente.
Linking Verbs
Por linking verbs entende-se os verbos que, basicamente, fazem a ligação entre o sujeito da sentença e o que se diz do sujeito.
Os verbos mais comuns são: be, seem, look, feel, appear, become, grow, sound, taste, go, get, smell, prove.
Exemplos:
I am proud of my students. achievements.
All the participants seemed happy.
The class activity proved to be interesting.
It is becoming darker and darker. Let.s take a cab!
His idea sounds good, doesn't it?
This pasta tastes awful. What's wrong with it?
After the crash of the Concorde, everybody wants to know what went wrong and what the future of supersonic travel is.
Some people say this world is going crazy.
My ancestors were farmers.
I am getting hungry. How about going to the school cafeteria?
Contrary to parents' expectations, the two brothers became Catholic priests.
Betty seems (to be) the ideal person to look after (take care of) the children.
A new supermarket has been built round the corner. (Passive Voice)
A: What does your brother do for a living?
B: Don't you know? He is a physician (doctor of medicine).
Auxiliary verbs
Vão ajudar dar sentido ao verbo principal. São eles:
a. am, is, are, was, were
b. have, has
c. do, does, did
d. will
Exemplos:
A: It.s 1 p.m. I am starving. (Present Progressive or Continuous)
B: No kidding!
I don't believe it's raining again! It will spoil my Sunday! (Simple Future)
I have already finished reading the book for my Literature class. (Present Perfect)
Has your sister returned from work yet? (Present Perfect)
Nothing will prevent me from succeeding! I am determined to succeed.
Do you ever go to church on Sundays? (Simple Present)
Does your brother speak Spanish? (Simple Present)
Did you visit the Tower of London when you were there? (Simple Past)
Modal Verbs
São verbos que dão ao verbo principal, sempre na forma infinitiva, um determinado sentido ou sinalizam uma determinada função (proibição, não necessidade, habilidade, etc...) e, assim, não são usados de forma isolada; funcionam como auxiliares e nunca mudam a forma.
São os seguintes: can / could, may / might, ought to (= should), must, have (has) to / had to,
need, além das expressões had ('d) better e would ('d ) rather.
Can/could
Can e could (além de would) podem ser usados para solicitar alguma coisa ou pedir a alguém para fazer alguma coisa.
Exemplos:
Can I use your cell phone?
Could you close the door?
Would you mind opening the window?
Can e could (além de may -. forma mais polida) podem ser usados para fazer um pedido ou pedir permissão para fazer alguma coisa.
Exemplos:
Can I leave five minutes earlier?
Could I help with the box?
May I come in?
Quando a permissão é dada ou recusada (no tempo presente), podemos usar tanto can quanto may.
Exemplos:
You can't use this computer now; it is out of order and will be repaired tomorrow.
You may not sit here. Choose another seat.
The students can.t take more than three books from the library at a time.
You can use any of these dictionaries.
Students can (= are allowed to) wear jeans in my school.
You can't (= are not allowed to) park here. The sign says "No Parking".
No tempo passado, could (= was, were allowed to) deve ser usado para falar sobre permissão ou para reportar ideias.
Exemplos:
I couldn.t use the phone for personal calls when I worked there.
Pete said that his brother could use his car.
Can (present) e could (past) são usados para falar de habilidades que uma pessoa tem (não tem) ou tinha (não tinha).
Exemplos:
When my mother was young, she could dance beautifully.
Ronald can play soccer very well.
I can't talk to Mr. Nakamura as I don.t speak Japanese.
Sorry, I can.t understand you.
I couldn't swim when I was a child.
Uma outra maneira de expressar habilidade é usar know how to.
Exemplo:
I don.t know how to play the piano.
My sister knows to deal with this equipment.
Must (has to, have to)
Indicam que há necessidade de se fazer alguma coisa.
Exemplos:
You're my son. You must tell me the whole truth.
Sorry, I can't go with you. I have to go to the dentist right now.
You must fill out the form in ink. Also, you have to sign your name in full.
Must também é usado para indicar um fato aparentemente óbvio ou uma dedução da qual temos certeza:
Exemplo:
There are no lights on in the house. Evelyn must be out.
You must be tired. You worked hard all day long.
A: Chris told me she lived in the U.S. for three years.
B: Her English must be good.
Mustn't indica proibição:
Exemplo:
Students mustn't enter the classroom after 7 o.clock.
Should / Ought to
Should é usado para dizer que é aconselhável (ou não) fazer alguma coisa.
Exemplos:
X-Men'. is a great movie. You should see it.
I shouldn't live under so much pressure. I know it is not good for my health.
Cars in Brazil cost a lot of money. They ought to cost less.
You shouldn't leave your baggage unattended. Keep an eye on it.
Had better tem sentido mais enfático que should, sugerindo que, se algo não for feito, poderá haver alguma consequência.
Exemplos:
A: I don.t feel OK today.
B: You'd better go home.
This is my first school day. I.d better not be late.
May / might
Expressam probabilidade.
Exemplo:
A paragraph may be as short as a single word or as long as many pages.
You might be surprised when you hear the news today.
Would rather
É uma expressão que dá o sentido de preferência.
Exemplos:
A: What did Monica tell you yesterday?
B: I.d rather not say.
It's getting too smoky here. I'd rather leave the room. Let.s talk some place else.
Should have + past participle alguém lamenta não ter feito alguma coisa ou feito alguma coisa errada
Exemplo:
The Beach' is not on any more. You should have seen it.
I shouldn't have said that. It was very rude of me.
Must have + past participle dedução lógica de que algo aconteceu no passado.
Exemplo:
Your grade is 10. You must have studied a lot for this test.
Could have + past participle alguma coisa foi possível, mas não aconteceu.
Exemplos:
When I was in Lisbon, I could have stayed at the Hilton, but I decided to save some money and chose a cheaper hotel.
Davidson could have been selected for this position if he had been applied for as he is highly qualified.