Everyone has a responsibility to save _____ water, if future generations are to enjoy a similar standard of living to _____ we enjoy now.
. She insisted that she ______ somebody in the house.
——I must apologize for _______ ahead of time.——That's all right.
If you had not helped them, they ______ in London now.
A piece of ______ music will make you happy.
Greatly ______, the students made up their minds to work at English even harder.