In developing countries people are ________ into overcrowded cities in great numbers to hunt for fortunes.
The expert says that nowadays there are too many problems linked to poor diet and a ________of exercise.
_____ new cure for this disease that medical experts have recently developed proves to be ______ most effective, although it can not completely kill all the viruses.
— What do you think of the novel written by the well-known writer? — Sorry, no _________!
If my father ______ here yesterday, he would have stopped me from going surfing.
In my opinion, we need to begin ______ we stopped yesterday to ensure we won’t miss anything.