back then片語KK [bæk ðɛn] /bæk ðɛn/發音片語1當時、那時候、那時Back then, most people still wrote letters by hand.那時候大多數人還是手寫信件。2早年、以前口語Houses were much cheaper back then than they are now.以前的房價比現在便宜得多。