It is the prevention of disease ________ its successful treatments that has led to the rapid increase of the world’s population.
Hefailedintheexamination,________madehisfatherveryangry.
There is no doubt ________ he will succeed.
________ my surprise, ________ I could have a word with him, he left.
The school ________I studied for only two years was three kilometers away.
After ________ hard, I got a job in a gold mine.