Since that time, new methods of extracting more oil from existing oilfields, and the ability of the oil industry to operate in hostile environments which were previously thought to be out of bounds , have greatly extended the supply of hydrocarbons on world markets and tended to push this scenario somewhat into the background.
(new methods of extracting more oil from existing oilfields, and the ability of the oil industry; have extended; the supply of hydrocarbons on world markets; T:Since that time) (new methods of extracting more oil from existing oilfields, and the ability of the oil industry; tended; to push this scenario somewhat into the background; T:Since that time) (hostile environments; to be; out of bounds)
new methods of extracting more oil from existing oilfields, and the ability of the oil industry new methods of extracting more oil from existing oilfields, and the ability of the oil industry hostile environments
have extended tended to be
the supply of hydrocarbons on world markets T:Since that time
to push this scenario somewhat into the background T:Since that time
out of bounds