Uncle Li is hardly ever tired. He’s really        .

Mary is _____ than her cousin. 

Many people are wearing gloves and coats. So I think it is _________ outside.

—What do you think of the report about the air pollution on TV last night?—I think the situation is so        that we should take action to protect the environment.

—Do you enjoy traveling by air?     —No, it’s ________ expensive.