—What would you do if it________tomorrow?—We have to carry it on, since we've got everything ready.
Do you know the police ______ searching for a thief in the woods now ?
When he was young, his parents died and he had to _____ himself.
Whether life will continue on the earth will depend on _______ this problem can be solved.
Only when it is hungry______ a human being.
In such a cold day, people prefer to stay at home _______ go out.