1. Oscar Ayala
2. Expression 1:
2.1. to regret
2.1.1. Structure positive: to regret+ ing verb (gerund)
2.1.1.1. Example:
2.1.1.1.1. I regret staying out in the sun
2.1.1.1.2. I regret not putting sunscreen
2.1.2. Structure negative: to regret + not + ing verb (gerund)
2.1.2.1. Example:
2.1.2.1.1. I regret not putting sunscreen
3. Expression 2:
3.1. should have
3.1.1. Structure: should+have+past participle
3.1.1.1. Example:
3.1.1.1.1. I should have tried on first
3.1.2. Structure negative: should+not+have+past participle
3.1.2.1. Example:
3.1.2.1.1. I shouldn't have ignored my sister
4. Expression 3:
4.1. Third conditional
4.1.1. Structure
4.1.1.1. Clause 1
4.1.1.1.1. if+past perfect
4.1.1.2. Clause 2
4.1.1.2.1. would (not)+have+past participle
4.1.1.3. Invert the clauses
4.1.1.3.1. Whichever clause is first carrier more emphasis
4.1.1.4. Example
4.1.1.4.1. If I had put more petrol in, we would have been fine
5. Expression 4 and 5
5.1. I wish and If only
5.1.1. Structure
5.1.1.1. I wish/If only + past perfect
5.1.1.1.1. Example