He accidentally _____ he had quarreled with his wife and that he hadn’t been home for a couple of weeks.
.The wallet _______ several days ago was found _______ in the dustbin outside the building.
.Lessons _______ easily were soon forgotten.
The ground is _______ with _______ leaves.
The library's study room is full of students _______ for the exam.
The scientists were waiting to see the problem _______.