Too fast - grammar books are best

Also he's wrong on some points, such as claiming that "effect" can only be a noun and not a verb when it can be both:

to affect means 'to exert an influence upon,' and implies the action of a stimulus that can produce a response or reaction, whereas to effect means 'to bring about as a result' [online dictionary]

and anyways , as we all know, there's no noun that can't be verbed