The development of industry has been ____ gradual process throughout ______human existence, from stone tools to modern technology.
The Smiths ______ their breakfast when the doorbell rang.
The majority of doctors ______ smoking is harmful to health.
EitherJimorI ____goingtohelpthefarmerswiththeorangeharvestthisafternoon.
A good deal of money ____spent on books.
It ____I who _____leaving for London.