1.She has conducted on London buses for twenty years.
她在伦敦公上担任了二十年的售票员。
2.The campus is different from how it was 20 years ago).
校园和二十年前的样子不一样了)。
3.We may as well assert that because a child has thriven upon milk, that it is never to have meat, or that the first twenty years of our lives is to become a precedent for the next twenty.