By the middle of the 21st century, the vast majority of the world's population __________ in cities rather than in the country.
There was a(n)________silence in the live interview,when no one knew what to say to the audience.
--Time and tide wait for no man. ---________. We should value our time.
_______ yesterday, our school organized a successful picnic in the countryside, with all the students and teachers taking part in.
—Do you have anything to say for yourselves? —Yes, there is one point _________ we must insist on.
It was in so poor light that I couldn't _________ what the newspaper said.