She ________ (not / realise) that she ________ (make) a serious mistake until her supervisor pointed it out.

I ________ (just / finish) my presentation when the computer suddenly ________ (crash).

Whenever we used to visit my grandparents, my grandfather ________ (tell) us stories about his childhood, while my grandmother ________ (make) us something to eat.

I ________ (lose) touch with several friends since I ________ (leave) university.

As a child, I ________ (spend) every summer at my grandparents' house, and my cousins ________ (come) to stay with us for weeks at a time.

She ________ (work) incredibly hard recently, and she ________ (already / complete) most of the project.

I ________ (meet) her several times before I ________ (discover) that we had a mutual friend.

I ________ (never / understand) why he left the company until he ________ (tell) me what had happened.

When the lecture ________ (begin), several students ________ (still / look) for somewhere to sit.

When I was younger, I ________ (think) that success ________ (depend) entirely on how intelligent someone was.

She ________ (already / leave) by the time I ________ (arrive) at the office.

They ________ (not / speak) to each other for several years before they unexpectedly ________ (meet) at a conference.

The company ________ (experience) serious financial difficulties for months before the directors ________ (announce) the closure.