Mr. Smith graduated from college at the age of 23, and ___________ he has been working as a teacher in a middle school.
Children are not recommended to see such films bad for their mental development.
Because of Einstein’s Theory of Relativity, scientists never again regarded the world .
--- Hurry up. The bus is coming. --- Oh, no. We mustn’t cross the street the traffic lights are green.
Sorry, you lost your purse; I hope it will some day.
A brilliant idea occurred to him, to his research in the lab.