had been substantiating

• 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 substantiate.
  substantiate

  verb (used with object)

  to establish by proof or competent evidence.

Related Words

• affirm
• confirm
• corroborate
• debunk
• demonstrate
• justify
• prove
• ratify
• validate
• verify