something'

eg：complained to the manager, and by this procedure got the money back.

2) "A series of steps taken to accomplish an end"

6. undertake v.

1) "To take upon oneself; decide or agree to do"

eg：undertake a task.

2) "To pledge or commit (oneself) to'

eg：undertake oneself to care for an elderly relative.

7. breakthrough n.

1) "An act of overcoming or penetrating an obstacle or restriction."

2) 'A military offensive that penetrates an enemy's lines of defense'

eg: a ~ in cancer research

8. disturb v. "break the quiet, calm and peace'

eg: She opened the door quietly so as not to disturb the sleeping boy.

Don't ~ the papers on my desk.

9. arbitrary adj.

1) "Determined by chance, whim, or impulse, and not by necessity, reason"

eg：stopped at the first motel we passed, an arbitrary choice; arbitrary division of the group into halves.

2) "Based on or subject to individual judgment or preference"