has been staining

• present perfect progressive

  present perfect progressive

  Used to describe an action that began in the past, has continued continuously, and is still in progress.

  of stain (3rd person singular).
  stain

  noun

  a discoloration produced by foreign matter having penetrated into or chemically reacted with a material; a spot not easily removed.

Related Words

• besmirch
• blacken
• contaminate
• daub
• discolor
• dye
• smear
• smudge
• sully
• tar
• tarnish
• tint