[ThinkingGuy]

One minor quibble with the author's example sentences: They use "watashi wa hito desu" to mean "I am a person."

I'm not a native Japanese speaker, but I'm pretty sure that "hito" is only used to refer to other people, never to oneself (source: the excellent "Nihongo Notes" series by the Mizutanis).

Maybe watashi ha ningen desu 私は人間です (I am a human) would be a better example that still illustrates the grammar pattern.