一Professor Li, ______the student start at once or wait a while? 一At once.
Something _______ wrong with the machine, and it _______ not work.
Today everyone arrived earlier than _______.
Just as the experts _______ it, this kind of material is not natural, but man-made.
¾ Are you waiting for a bus from Medical University? ¾ Yes. I arrived here at the bus stop ten minutes ago, but the bus _______.
¾ Who invented _______ cell phone? ¾ I don’t know. Maybe _______ European.