Strunk & White's Elements of Style, in this case:

http://chronicle.com/article/50-Years-of-Stupid-Grammar/25497

I've always said I'd never met a quotation from them which I didn't disagree with, but I hadn't realised just how wrong they are.

Emma

So that's where all that nonsense about eliminating "be" or "was" comes from. I had wondered.

Yes - and I'd always assumed it was stupid teachers mis-taking the book. But evindently not. I did a whole blog post on it, you might remember.

No wonder US editors, apparently, use 'passive' as an all-purpose term for weakish sentences, too. They genuinely don't know the difference between a true passive construction and other things which are nothing of the sort

Before I found WW, I was on a US site - won't name it, but that wretched book was revered as holy writ by pretty much everyone.

'Was' was pounced on as being 'passive tense' (sic), and woe betide anyone who attempted to explain otherwise, or suggest something so daft couldn't possibly be a rule...

I know just the attitude you mean. Not to mention the "was" thing - although it was a long time before I could believe that its source was something genuine, not just chinese whispers among aspiring writers... I finally lost patience with trying to unpick the depths of that one, and blogged about it:

http://emmadarwin.typepad.com/thisitchofwriting/2011/05/have-you-heard-the-one-about-was.html

Great article, but how sad. I have great sympathy with today's students who are being mistaught by teachers who were themselves victims of the virtual abandonment of grammar by the educational establishment at the end of the sixties. Until then most writers, beginners included, had benefited from a classical element in their education (Latin at least) at some level, however minimal. Explaining the mysteries of tense, voice, mood, aspect, gerunds, etc., to somebody without that background is difficult but not impossible. I am not saying that everybody should now be taught Latin, but for the system not only never to have attempted to explain the principles but instead to have been mis-teaching the subject is nothing short of shameful.

The 'was' rule, apart from being ludicrous, is about as useful and practicable as the example of writing a story without using the letter 'e' as demonstrated in Raymond Queneau's magnificent 'Exercises de Style'.

Chris

Until then most writers, beginners included, had benefited from a classical element in their education (Latin at least) at some level, however minimal.

I have always believed, and occasionally said, that it would benefit any English-speaking person who wants to understand grammar to learn another language. I learned almost all of the grammatical concepts that I know from studying French and Russian at school, and that knowledge equips me to be able to tell the difference between a passive and an active sentence (for example).