Used to ask for and give permission

Used as more polite and more formal in asking permission (which may not be given)

The most polite and formal modal used in asking and giving permission

Used in dealing with something against the rules, laws and signs. The speaker is not the one who sets the rules.

Used in dealing with something that is not permitted. The speaker is the one who sets the rules.

Used when obligation comes not from the speaker. Used to express obligation set by an authority, rule or law.

Used when expressing obligation that comes from the speaker or from an authority.

Used ro express absence of commitment.

Statements expressing the result of a particular condition.

Clause that present the condition

Clause that explains results.

Habitual, general truth, laws

Likely to happen in the future

(If/When Clause) Simple Present (Main Clause) Simple Present

(If/When Clause) Simple Present (Main Clause) Will + base

Impossible things

Regret

(If Clause) If + simple past (Main Clause) Would + infinitive

(If Clause) If + had + past participle (Main Clause) Would have + past participle

Uses slang, vulgarities and colloquialism and informal contractions.

Used in semi-formal communication where sentences tend to be shorter and spontaneous. Normal style for speaking to strangers.

Straight forward speeches, avoids using slangs and uses formal english.

Generally used in a very formal setting. Rarely or don't change.

Usually done in private, and shows no social boundaries.