Scientists have many theories about how the universe ___ into being.

  The increasing number of cars on the road _______ traffic. This was the reason why we couldn’t get here on time.

Diets are most effective when _____ with exercise.

He ______ his sister to give up the plan for cycling along the Mekong River, but failed. 

The young man, who had rushed into the fire to save the old man, _____ rewarding.