=> If she hadn't threatened him, he wouldn't have asked her to leave.

=> If we had time, we would have visited the museum.
=> If the lift had been working, I wouldn't come up the stairs

 Landlord: She threatened to set fire to her flat ; that's the only reason I askeed her to leave

=> If she hadn't threatened him, he wouldn't have asked her to leave.

 we đin't visit the musrum because we hadn't time

=> If we had time, we would have visited the museum.
I only came up the stairs because the lift wasn't working

=> If the lift had been working, I wouldn't come up the stairs.