the Internet is of great help. I don't think it's a good idea to spend too much time on it.
Please ______ that you have closed all the windows and turned off the lights before you leave the room
When he was sixty years old, he _____ his hometown.
______ you understand the rule, you can do it well.
The room ____ voices of the children.
I can hardly heat the radio. Would you please ______?