Would is an auxiliary verb - a modal auxiliary verb. We use would mainly to:

We also use would for other functions, such as:

Structure of would

The basic structure for would is:

subject + auxiliary verb
+ main verb

Note that:

Look at the basic structure again, with positive, negative and question sentences:

  subject auxiliary
not main verb
+ I would   like tea.
- She would not go.  
? Would you   help?  

Note that the main verb is sometimes in the form:

The main verb cannot be the to-infinitive. We cannot say: He would to like coffee.
Be careful! Note that would and had have the same short form 'd:
He'd finished = He had finished
He'd like coffee = He would like coffee

Use of would

would for the past

We often use would as a kind of past tense of will or going to:

Using would as as a kind of past tense of will or going to is common in reported speech:

We often use would not to talk about past refusals:

We sometimes use would (rather like used to) when talking about habitual past behaviour:

would for the future in past

When talking about the past we can use would to express something that has not happened at the time we are talking about:

would for conditionals

We often use would to express the so-called second and third conditionals:

Using the same conditional structure, we often use would when giving advice:

Sometimes the condition is "understood" and there does not have to be an "if" clause:

Although there is always a main verb, sometimes it is understood (not stated) as in:
  • I'd like to stay. | I wish you would. (would stay)
  • Do you think he'd come? | I'm sure he would. (would come)
  • Who would help us? | John would. (would help us)

would for desire or inclination

would for polite requests and questions

would for opinion or hope

would for wish

Note that all of these uses of would express some kind of distance or remoteness:
  • remoteness in time (past time)
  • remoteness of possibility or probability
  • remoteness between speakers (formality, politeness)

would for presumption or expectation

would for uncertainty

would for derogatory comment

would that for regret (poetic/rare)

This rare, poetic or literary use of would does not have the normal structure: