86.
Dead ends never _________ scientific progress. ___________ they were always a factor that induced researchers and thinkers to_____________ the commonly held beliefs of their time, __________________ a breakthrough
A:
led to I Indeed I delve into I thus occasionally achieving
B:
interfered with I Indeed I be satisfied with I while abandoning any attempt to achieve
C:
furthered I On the contrary I cling to I thus often achieving
D:
hindered I On the contrary I question I which enabled them to reach
The answer is:
D