will have been crumbling

• future perfect progressive

  future perfect progressive

  Used to describe a continuous action that will progress up until a designated point of completion in the future.

  of crumble.
  crumble

  verb (used with object)

  to break into small fragments or crumbs.

Related Words

• break up
• collapse
• crush
• decay
• degenerate
• deteriorate
• disintegrate
• dissolve
• grind
• tumble