Complex sentence: He finished 33rd without ever completing a lap. In 1971 was entered in another car but when Lee Roy Yarbrough crashed hard with one of Dan Gurney's Eagles, his injuries was severe enough that he could not compete in the Indy 500 in 1971.
Split into simpler sentences: He finished 33rd without ever completing a lap. In 1971 was entered in a car. When Lee Roy Yarbrough crashed hard with one of Dan Gurney's Eagles, his injuries was severe enough that he could not compete in the Indy 500 in 1971.