yes·ter·day /ˈjɛstɚ/
  昨天,昨日(ad.)昨天,昨日
  Yes·ter·day, adv. On the day last past; on the day preceding to-day; as, the affair took place yesterday.
  ◄ ►
  Yes·ter·day n.
  1. The day last past; the day next before the present.
  All our yesterdays have lighted fools
  The way to dusty death.   --Shak.
     We are but of yesterday, and know nothing.   --Job viii. 9.
  2. Fig.: A recent time; time not long past.
     The proudest royal houses are but of yesterday, when compared with the line of supreme pontiffs.   --Macaulay.
  yesterday
       n 1: the day immediately before today; "it was in yesterday's
            newspapers"
       2: the recent past; "yesterday's solutions are not good
          enough"; "we shared many yesterdays"
       adv 1: on the day preceding today; "yesterday the weather was
              beautiful"
       2: in the recent past; only a short time ago; "I was not born
          yesterday!"