Rain is pouring down from the sky without any sign of stopping.Farmers begin to worry about their crops since it _____ as long as 24 hours.
If it _____ another ten minutes, the game would have been called off.
Waving to her family on the platform, _____.
The novelist knew little about the precious document(文件). _____, he had hardly heard of it before.
Scientists and doctors across the world have done _____ research over the years, hoping to find a cure for cancer.
I don’t think _________ possible to master a foreign language without much memory work.