Lilith gave a good answer. Here is some more information: For a hypothetical completed action in the past ... would have <past participle of verb > ... would have done ... would have cooked For a hypothetical state in the past ... would have <past participle of "to be" > ... would have been sick ... would have been here For a hypothetical action in progress in the past ... would have been <present participle of verb> ... would have been doing ... would have been cooking Here is more information about conditionals: https://www.ef.com/ca/english-resources/english-grammar/conditional/

Not necessarily. Depending on the context and the sentence structure, it may refer to past, present, or future. What is your example sentence?

This is PERFECT CONTINUOUS CONDITIONAL. The perfect continuous conditional can be used in type 3 conditional sentences. It refers to the unfulfilled result of the action in the if-clause, and expresses this result as an unfinished or continuous action. For example: If she hadn't got a job in London (but she did), she would have been working in Paris (but she wasn't). or If the weather had been better (but it wasn't), I'd have been sitting in the garden when he arrived (but I wasn't).