Conditional tense

Zero Conditional
If I heat water, it boils
IF + PRESENT SIMPLE, PRESENT SIMPLE

First Conditional
If I have money, I’ll buy this car for you.
IF + PRESENT SIMPLE, WILL/WON’T + INFINITIVE

2nd Conditional
If I had money, I would buy this car for you
IF + PAST SIMPLE, WOULD/WOULDN’T + INFINITIVE

3th Conditional
If I had had money, I would have bought this car for you
IF + HAD + PAST PARTICIPE, WOULD HAVE + PAST PARTICIPE

Infinitive or –ing form?

When to use the infinitive?

The infinitive form is used after certain verbs:

- forget, help, learn, teach, train
- choose, expect, hope, need, offer, want, would like
- agree, encourage, pretend, promise, recommend
- allow, can/can’t afford, decide, manage, mean, refuse

I forgot to close the window.
Mary needs to leave early.
Why are they encouraged to learn English?
We can’t afford to take a long holiday.

The infinitive form is always used after adjectives, for example:

- disappointed, glad, happy, pleased, relieved, sad, surprised

I was happy to help them.
She will be delighted to see you.

➡ This includes too + adjective:
The water was too cold to swim in.
Is your coffee too hot to drink?
➡ The infinitive form is used after adjective + enough:
He was strong enough to lift it.
She is rich enough to buy two.
Use the Infinitive form to express reason or purpose
She’s saving money to buy a new car

When to use -ing?

The -ing form is used after certain verbs:

- avoid, dislike, enjoy, finish, give up, mind/not mind, practise, forgive, deny, miss, suggest, detest, practice, understand.

I dislike getting up early.
Would you mind opening the window?

The -ing form is used when the word is the subject of a sentence or clause:

Swimming is good exercise.
Doctors say that smoking is bad for you.
The -ing form is used after a preposition:
I look forward to meeting you.
They left without saying “Goodbye.”

Tip
Some verbs can be followed by the -ing form or the infinitive without a big change in meaning:

begin, continue, hate, intend, like, love, prefer, propose, start.

It started to rain.
It started raining.
I like to play tennis.
I like playing tennis.