18 ones* 19 were developed 20 known 21 breathes 22 to explore 23 most
famous 24 had been 25 their 26 are qualified 27 technological 28 Chinese
очень сомневаюсь, но нет там
других вариантов c ‘one’
Скорее всего это опечатка, там должно быть ‘the most commercially successful sets’