a·back /əˈbæk/ 副詞
 吃驚;
 參見 be taken aback
 A·back adv.
 1. Toward the back or rear; backward. “Therewith aback she started.”
 2. Behind; in the rear.
 3. Naut. Backward against the mast; -- said of the sails when pressed by the wind.
 To be taken aback. (a) To be driven backward against the mast; -- said of the sails, also of the ship when the sails are thus driven. (b) To be suddenly checked, baffled, or discomfited.
 Ab·ack n. An abacus.  [Obs.]
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 aback
      adv 1: having the wind against the forward side of the sails; "the
             ship came up into the wind with all yards aback"
      2: by surprise; "taken aback by the caustic remarks"