A: Yesterday you fell off the stairs.
B: I didn't fall off the staris yesterday.
A: He left the office at 10 PM.
B: He didn't leave the office at 10 PM.
A: She came back to retrieve her purse.
B: She didn't come back to retrieve her purse.
A: They met two years ago.
B: They didn't meet two years ago.
A: I was leaving the building when they called me.
B: You weren't leaving the building when they called you.
A: You were coming back from work when this happened.
B: I wasn't coming back from work when this happened.
A: He was getting up back then.
B: He wasn't getting up back then.
