Many young people don't work hard, and regret it later when the opportunity is gone.They only realize it________it is too late.

It is generally considered unwise to give a child ________ he or she wants.

It sounds like something is wrong with the car’s engine. _____ , we’d  better take it to the garage immediately.

 ____ is certain, though, is that “the curse of the mummy” remains a riddle to this day.

 You may give this message to _________ is at office.