I can think of many cases _______ students obviously knew a lot of English words and expressions but couldn’t write a good essay.
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 ______?