Fix grammatical mistakes in this sentence: They failed to consider that the broken reactors were the first generation reactors and technology by then was not mature and well developed.
The first generation of reactors were not mature and well developed.
The second generation reactors were not mature and well developed.
The third generation reactors were not mature and well developed.
The fourth generation reactors were not mature and well developed.
The fifth generation reactors were not mature and well developed.
The sixth generation reactors were not mature and well developed.
The seventh generation reactors were not mature and well developed.
The eighth generation reactors were not mature and well developed.
The ninth generation
The first generation of nuclear reactors were not developed until the second generation of reactors were developed.
Correct: The first generation of nuclear reactors were not developed until the second generation of reactors were developed.
Correct: The first generation of nuclear reactors were not developed until the second generation of reactors were developed.
Correct: The first generation of nuclear reactors were not developed until the second generation of reactors were developed.
Correct: The first generation of nuclear reactors were not developed until the second generation of reactors were