When do we use will, would, shall and should?

"Will" and "would" for predictions:

We can use "will" for a prediction:

• It's midnight, and James is still working. He'll be tired tomorrow.
• They're going to Delhi for the weekend.--That will be nice.

We use "would" for a past prediction or a prediction about a possible situation.

PAST:

• At midnight James was still working. He would be tired the next day.

POSSIBLE:

• How about going to Netherlands next weekend?--That would be nice. I wouldn't enjoy a camping holiday.

We can use "shall" instead of "will", and "should" instead of "would", but only in the first person, after " I " and  "We".

• I will/shall go to the party.
• We would/should like to come with you all.

WRONG USAGE:

• My friend should like to come with us. ----incorrect.

Shall and Should are a little formal here.

Would like:

We can use would like, usually shortened to 'd like, when we ask for something.

• I'd like to have coffee.
• We'd like to order our food now.
• This is a more polite way of saying: than saying----I want to have coffee.

We also use "would like" in offers and invitations.

• Would you like a free gift?
• Would you like to accompany us to the party?

Decisions and refusals:

We can use "will" for an instant decision or for an offer.

DECISION:

• Tea or Coffee? ---I'll have coffee, please.

OFFER:

• I'll wait for you if you like.--Thanks a lot. I won't take much time.

We use "won't" and "wouldn't" for a refusal.

• The strikers won't attend work until all their demands are met
• The key went in the lock, but it wouldn't turn.
• I won't....is a strong refusal.
• I won't listen to her anymore.

Shall and Should:

We use "Shall I".....?..in offers and "Shall we".....? in suggestions.

OFFER:

• Shall I wait for you?---Thanks a lot, I won't take much time.

SUGGESTION:

•  Shall we go to the party?---Good idea.

We use either "Shall" or "Should" to ask advice.

• I'm facing a terrible predicament. What shall/ should I do?

We use "Should" to say what is the appropriate thing to do.

• People should be honest.
• We should exercise regularly.
• You shouldn't be a spendthrift.