_____ into use in April 2000, the hotline was meant for residents reporting water and heating supply breakdowns.
Often he______ sit for hours doing nothing at all when he was in low spirits.
What he had said and done in the school ______ his parents and teachers.
—What are you anxious about? —_______.
The boss refused to sell the car for ________ he thought was not satisfactory.
―The river runs clear. ―We all appreciate the importance the local government has_______ the environmental protection.