had been calibrating

• 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 calibrate.
  calibrate

  verb (used with object)

  to determine, check, or rectify the graduation of (any instrument giving quantitative measurements).

Related Words

• adjust
• assess
• average
• check
• compute
• determine
• estimate
• evaluate
• fit
• gauge
• limit
• mark
• peg
• quantify
• rank
• regulate
• survey
• weigh