One day two crabs took a walk on the beach.
“Child,“”said the mother crab,
“you are walking quite funny. You should walk straight and keep your head up, not twist so much.”
“Mother,” said the young crab, “I am just copying you.”
We should always lead by example.

crab [kræb]：螃蟹
twist [twɪst]：扭成一束，捻
lead by example ：以身作则