Animal Metaphors:Casting pearls before swine is a Biblical idiom. Remind students it refers to wasting a "pearl" (wisdom/value) on "swine" (pigs) who won't understand its worth.
Social Idioms:Came out of his shell is a great way to describe a shy person becoming friendly, like a turtle stepping out of its protection.
• 25Idioms & Phrases Practice Alphabet "C" (Question Type M.C.Q)