Is that a hat? I teach English at various schools and colleges in Japan. In one of these places, there is a text-book for beginners that offers the following example: Ken: Is that a hat? Mary: No, it isn't. It is a scarf. My question is: How useful is this example? Does any normal human being often use this question? Or is it the kind of question that is only used in very rare circumstances- maybe if you are The Earl of Carnarvon exploring Tutenkhamen's tomb, or possibly Chief O'Hara , entrusted with protection of a priceless collection of Etruscan snoods. To consider some comparisons with examples in other subjects: Geography: An example of a country is: The Republic of Upper Volta . History: An example of an English Monarch is Sweyn Forkbeard . Biology: An example of a mammal is