translation.en: The DVD, as you know, was introduced in the mid-1990s and it was quite expensive. But you can see that by 1998, it had fallen below 400 dollars, and 400 dollars was a psychological threshold.
translation.zh: 众所周知，DVD 在九十年代中期开始进入市场。 那时它还很贵。但是到了1998年， 它的价格跌到了400美元以下，400美元是个关键的心理价位，