3rd conditional
if + past perfect / would + have + V3
1 On Sunday the guests had to have their lunch inside. Unfortunately it wasn't warm enough to have it outside.
if it had been warm enough outside on Sunday, the guests wouldn't have had their lunch inside.
2. There was a bomb scare last Tuesday. Sarah wanted to fly to Rome, but she wasn't able to. The airport was closed.
if there hadn't been s bomb scare last Tuesday and the airport hadn't been closed, Sarah would have flown to Rome.
3. Laura has only met Nick once, and it's possible she wouldn't recognize him. He passed her yesterday, but he had a crash-helmet on.
if Nick hadn't had a crash-helmet on then, Laura would have recognized him
4. Sarah has been quite busy, and she hasn't watered her plants for some time. As a result, they've died.
if Sarah hadn't been quite busy, she would have watered her plants forsome time and they wouldn't have died
5. Nick likes ice hockey, but he didn't have a ticket to the game last week, so unfortunately he wasn't able to get in.
if Nick had had a ticket to the ice hockey game last week, he would have been able to get it