________ fire, all exits must be kept clear.
The doctor had almost lost hope at one point, but the patient finally .
They lost their way in the forest, and . Which of the following is wrong?
The latest edition of Harry Porter has been a best-seller for 3 weeks_______.
If they _______ what I was saying, they'd know what I was talking about.
He ______ the math problem, his classmates wanted to help him out.