Common Errors in similes showing qualities of things / creatures!

Wrong: as clear as a crystal.
Correct: as clear as crystal.

Wrong: as hard as the iron
Correct: As hard as iron.

Wrong: as smooth as the glasses
Correct: as smooth as glass.

Wrong: as safe as a bank.
Correct: as safe as the bank.

Wrong: as silent as a grave
Correct: as silent as the grave.

Wrong: as hot as the furnace.
Correct: as hot as a furnace.

Wrong: as light as the feathers.
Correct: as light as a feather.

Wrong: as wise as a owl.
Correct: as wise as an owl.

Wrong: as sure-footed as the goat.
Correct: as sure-footed as a goat.