I don’t know who invented ________ telephone. It’s really ________ most useful invention.
— What do you think made him put into prison?—_______ stealing the valuables.
_____there be a flood this summer, what would we do?
You would have helped your mother do some housework. But you_______.
I have some difficulty in finding his house. I wish I_____his address.
Students are ____for new knowledge to suit themselves to the future jobs in various fields_______ which they are unfamiliar.