back then片语KK [bæk ðɛn] /bæk ðɛn/发音片语1当时、那时候、那时Back then, most people still wrote letters by hand.那时候大多数人还是手写信件。2早年、以前口语Houses were much cheaper back then than they are now.以前的房价比现在便宜得多。用这个字练口说→