Articles: a/an, the, no article

Use a / an with singular countable nouns.
The first time you mention a thing/person. I saw an old man with a dog.
When you say what something is. It's a nice day.
When you say that somebody knows. She's a lawyer.
In exclamations with What...! What a wonderful day!
In expressions like... three times a week

Use the
When we talk about something we've already mentioned. I saw an old man with a dog, and the dog was barking.
When there's only one of something. The moon goes round the earth.
When it's clear what you're referring to. He opened the door.
With places in a town. I'm going to the theater.
With superlatives. It's the best restaurant in town.

Don't use the
When you are speaking in general (with plural and uncountable nouns). Women talk more than men.
With some nouns after at / to / from. She's not at home today.
Before meals, days and months. I never have breakfast on Sundays.
Before next / last + days, week, etc. See you next Friday.

Blur - Parklife

Quantifiers

Large quantities
Use a lot of / lots of in (+) sentences
They have a lot of books.
She has lots of friends.
Use a lot when there is no noun. He studies a lot.
Much / many are normally used  in (-) sentences and (?), but a lot of can also be used.
There aren't many cafés near here.
Do you watch much TV?
Use plenty of in (+) sentences to mean as much as we need or more.
Don't run. We have plenty of time.

Small quantities
Use little + uncountable nouns, few + plural countable nouns.
Do you want some ice cream? Just a little.
The town only has a few cinemas.
A little and a few = some, but not a lot,
Very little and very few = not much / many.
Hurry up. We have very little time.
I have very few close friends.

Zero quantity
Use any for zero quantity with a (-) verb. Use no with a (+) verb.
There isn't any room in the car.
There's no room in the car.
Use none (without a noun) in short answers.
How much money do you have? None.

More than you need or want / less than you need
Use too + adjective, too much + uncountable nou, too many + plural countable nouns.
There's too much traffic.
Use enough before a noun but after an adjective.
There aren't enough pubs.

Usually and Use to

Present habits and states.
I usually get up at 8.00 on school days.
Past habits and states.
I used to go out with that girl when I was at school.

For present habits use usually or normally + present simple.
For past habits use used to / didn't use to + infinitive. Used to doesn't exist in the present tense.
We use used to for things that were true over a period of time in the past. It usually refers to something which is not true now.
Used to / didn't use to can be used with actions verbs (wear, go, ...) and non-action verbs (be, have, ...)
We often use not ... any more / any longer with the present simple to contrast with used to. I used to go to the gym but I don't any more/any longer.

Second conditional

Second conditional sentences: if + past simple, would/wouldn't + infinitive
Use the second conditional to talk about a hypotetical/imaginary situation in the present or future and its consequence.
Compare:
Real situation: I don't have much money, so I can't buy a bigger house.
Hypotetical situation: If I had money, I'd buy a bigger house.
Use the second conditionals beginning If I were you, I'd ... to give advice. Here you can't use If I was you.

Would / wouldn't + infinitive
You can also use would / wouldn't + infinitive (without an if clause) when you talk about imaginary situations.
My ideal holiday would be a week in the Bahamas.
The contraction of would is 'd.

!!!!!!
Remember the difference between first and second conditional:
If I have time, I'll help you. A possible situation. I may have time.
If I had time, I'd help you. An imaginary/hypotetical situation. I don't / won't have time.

First conditional and future time clauses + when, until, etc.

First conditional sentences: if (or unless) + present simple, will/won't + infinitive

Use the present tense (Not the future) after if in first conditional tenses. If you don't do more work, you'll fail the exam.

Unless = If ... not. I won't go unless she invites me. I won't go if she doesn't invite me.

You can also use an imperative instead of the will clause. Come and see us next week if you have time.

Future time clauses

Use the present simple (Not the future) after when, as soon as, until, before and after to talk about the future.

I'll call you as soon as I arrive.

We'll have dinner when your father gets home.

I won't go to bed until you come home.

I'll have lunch before I leae.

After I finish university, I'll probably take a year off and travel.

Can, could, be able to (ability and possibility) II

Más información y ejercicios sobre estos modal verbs:

http://www.englishclub.com/grammar/verbs-modals_can.htm

http://elblogdelingles.blogspot.com/2006/05/lesson-17-can-could-and-be-able-to.html

http://www.autoenglish.org/gr.can.i.htm