Complete the sentences with the superlative form of the adjectives in parentheses.
Kelly: I think people are too concerned about having (1) ___________________ (modern) cell phones. Cell phones contain some of (2)___________________ (rare) minerals on Earth, but many people just throw their old cell phones away when they buy a new one. This is (3)________________(one of the / bad / thing) you can do! But if you recycle your old cell phones, it’s (4)_________________(one of the / good / thing) you can do.