Hardly a week goes by without some advance in technology that would have seemed incredible 50 years ago.

【正确答案】 D

【答案解析】hard to invent“难以发明的”；hard to understand“难以理解的”；hard to imagine“难以想象的”；hard to believe“难以置信的”。incredible“难以置信的”，与“hard to believe”意思相近。故选D。