She _______________ (visit) her grandmother for 2 years before her grandmother passed away.
The doctor ____________ (practice) surgery for 20 years before he retired.
The pied piper ______________ (attract) the mice with the music of his flute for many days before he guided them to the river to be drowned.
The scientists _____________ (recover) data for their experiments much before the professor asked them to do so.
The child ______________ (play) for an hour before his teacher arrived.
The teacher was very angry as he ____________ (wait) for a long time before we arrived.
When the teacher entered the classroom on Monday, her eyes were red. I think she __________ (cry).
When we saw the boy on the pavement, he seemed very frail and tired. I think he ____________ (not/eat) for many days.
When he woke up, he realized that he _____________ (sleep) for 15 hours!