【单选题】
____ native to North America, corn has now spread all over the world.
【单选题】
Bit by bit, a child makes the necessary changes to make his language ____.
【单选题】
Please____ me whether I should accept the offer.
【单选题】
All the flights ____ because of the snowstorm, we had
to take the train instead.
【单选题】
Everything is right here, _____?
【单选题】
A camera takes light rays bounced off objects and____ them
on a sheet of a film.
【单选题】
It has been proposed that we ____ our decision until the next meeting.
【单选题】
By the middle of the 21st century, the vast majority of the world’s population ____ in cities rather than in the country.
【单选题】
Mary tiptoed over and took the clock away
because she hated to hear it ____ when she was
trying to go to sleep.
【单选题】
Under this ____ pressure some of the rocks
even became liquid.