укажите предложения а. с неопределенно-собственным местоимением oneб. со словом one заменителем

Укажите предложения а. с неопределенно-собственным местоимением one
б. со словом one заменителем ранее упомянутого существительного
в. с числительным one

1. The efficiency of the new method is much higher than the efficiency of the old one. It differs greatly from the one used at our enterprise/
2.One might say that at the end of World War II the United States was the only strong capitalist country with most of the gold reserves.
3. The people of Britain live in one of the most beautiful islands in the world.
4. One must learn English words for very lesson.
5.This article is more difficult than the one we translated last week.