touchstone

名词 touchstone:

1. a basis for comparison; a reference point against which other things can be evaluated
   同义词：standard, criterion, measure

1. As the touchstone tries gold, so gold tries man.
   试金之石可试金，正如黄金能试人。
2. The greatest touchstone of any work is time.
   时间是检验一切的最好的试金石。
3. Love is the touchstone of virtue.
   爱情是美德的试金石。