You know, people keep telling me that I shouldn't blame Strunk & White for the way so many Americans are clueless about identifying passive clauses. Others tell me I'm being prescriptive: I should let people use the word 'passive' however they want. (And you can, of course; you can use it to mean "box containing electrical equipment" if you want.) But I'm unrepentant in my conviction that page 18 of The Elements of Style has been confusing people for decades. Let me give you (if you can bear it) another example of why.
Danny Rubin, on his Lifehacker blog, gives a writing demonstration. He starts with this example of what he says is bad writing that needs to be improved:
After the changes he proposes, he wrestles the above into this form:
What did he change and why? This is how he begins to answer that question:
First, I switched the voice from passive to active (from 'there is' to 'you'). Always locate your subject and lead with it. Active voice feels confident; passive does not.
Changing there is to you don't, of course, has nothing whatever to do with the passive or the active. I have no idea what Danny Rubin thinks the passive voice might be. But I know that grammar teaching in the USA is in a lot of trouble if he is telling people how to write and he thinks There is a common misconception is a passive.