Every time Ashtita tries to break a record, he reaches a point ______ he feels he cannot physically do any more.

A．where

B．that

C．when

D．which

一个技术从酝酿到投入市场为止所经历的时间叫______

A．技术革新周期
B．生命周期
C．狭义的技术寿命期
D．开发周期