The population of China ________ 1.3 billion，and 80% of the population________farmers.

Rather than____a bike in the freezing weather she preferred____on a crowded bus.

Never before _____so highly successful in his attempts to change the weather slightly on a very small scale. [ ]

His determination and devotion to science________his great discovery.[ ]

All the students are talking and laughing in the classroom and it’s _______.