-Can I come to see you at ten o'clock, John?-I'm sorry, Jo, but I __________ my uncle then.
She had no idea how it ______ that her husband met with trouble again.
Ten years ago the population of our village was ____________ that of theirs.
The hat borrowed from the drama company was so dirty that it required ________ thoroughly.
I felt very strange __________________.
________ had been done, the working efficiency of the employees still remained low.