Why did you walk home? Why didn’t you take a taxi? You ... have walked home.

I’m sorry that I didn’t take your advice. I ... what you said. (do)

unusual in terms of someone’s personality

Two dancers came in secret / out of nowhere and started dancing.

used to show the total amount of smth

responsible for smth bad that has happened

before a particular time, or before doing a particular thing

Patrlce broke his leg on a skiing trip and he wasn't able to become a footballer.=>Patrice ... a footballer if he hadn't broken his leg on skiing trip.

There were probably about 40 dancers in detail / all.

Why did they stay at a hotel? Why didn’t they stay with us? They ... have stayed at a hotel.

It must have been planned by accident / in advance.

without intending to