has been prolonging

• 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 prolong (3rd person singular).
  prolong

  verb (used with object)

  to lengthen out in time; extend the duration of; cause to continue longer.

Related Words

• continue
• delay
• drag out
• lengthen
• perpetuate
• protract
• stall