over time

名词 over time:

1. work done in addition to regular working hours
   同义词：overtime
2. playing time beyond regulation, to break a tie
   同义词：overtime, extra time

副词 over time:

1. beyond the regular time
   同义词：overtime

1. As a result, nacre thickness is sometimes just a cosmetic layer that can wear thin over time.
   所以真珠质的厚度就像脸上化妆品，不久就会磨薄了。