— My computer _______ start, no matter how hard I try.— It might have crashed.
He was ______ medical student before he turned _______ engineer.
He’s so ill that his father has to send for _______ doctor.
The price of _______ bike will partly be determined by the sort of ______ material used.
Jumping out of _______ train running at a speed of 200 kilometers per hour is quite _____ dangerous practice.
---Are you satisfied with what the captain explained? ---Not at all. It couldn’t have been________.