had been keying

• past perfect progressive

  past perfect progressive

  Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.

  of key.
  key

  noun

  a small metal instrument specially cut to fit into a lock and move its bolt.

Related Words

• basic
• crucial
• decisive
• fundamental
• indispensable
• leading
• main
• major
• pivotal
• primary
• principal
• vital