had been streamlining

• 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 streamline.
  streamline

  noun

  a teardrop line of contour offering the least possible resistance to a current of air, water, etc.

Related Words

• build
• carve
• construct
• embody
• fashion
• forge
• frame
• mold
• produce