We were ________ on our way to the airport in a traffic jam.
--- I wonder if I could use your telephone? --- _________.
The watch ______ unnoticed for several days before I found it.
—What do you think of his opinion?—None has given me ___________ piece of advice.
It has been proved _______ eating vegetables in childhood helps to protect you against serious illnesses in later life.
It is reported that the United States uses ____ energy as the whole of Europe.