The scientists predict that if present trends____, women in 400 years will be 2cm shorter and have healthier hearts.
So sudden ________that the residents had no time to escape.
— How long will it be _______ the president pays another visit to China?— It all depends.
Look! the ground is wet. It must have rained last night, _______?
Generally speaking, _______ according to the directions, the drug has no side effect.
Tom is _______ learning English. To learn it well, he abandons all his hobbies.