"The old key is always on." -Ben Franklin
"The present is the key to understanding the past"-Lyle
"The ideal book is the key to wisdom." -Tolstoy
Children are the key to heaven. -American writer Richard stoddard's Children's Prayer
Politeness is the golden key to human coexistence. -Spanish novelist Juan Antoniode
The question mark is the key to any science. Balzac, French writer