A good teacher will use the book in a way to point out the errors to the students, offering alternative ways of saying things than the book says.

True enough, WW. But why can't the Chinese choose a decent book in the first place? After all, textbooks are a teacher's tools. Akin to a carpenter's tools, good ones can make the teaching task more effective and efficient. Would you want to buy a dining table made by a carpenter with a blunt chisel and a saw with about as many teeth as I, being an oldtimer, have? Of course not!