As a linguistics major, I have developed a nervous tic from seeing far too many pieces of writing advice that are just plain wrong. It irks me to no end because people read it and parrot it and it spreads faster than a 4chan meme.
I want to talk to you today about passive voice. Passive voice happens when the subject and the object are reversed so that the object comes first.
Active: John (subject) hit (verb) the ball (object).
Passive: The ball(object) was hit(verb) by John (subject).
Active: John robbed the bank.
Active: John was robbing the bank.
Passive: The bank was being robbed by John.
Now, in the second example, the second active sentence has the verb 'To Be' followed by an -ing, which a lot of people will tell you is passive. When they do, tell them that they're talking out of the wrong hole. It is NOT passive because the subject (John) is performing an action (robbing) to the object (the bank).
Of course, the first active sentence uses only an action verb (robbed), and so seems more dynamic. This is where the confusion arises. Yes, if possible it is better to avoid the verb 'To Be' in favour of an action verb. But its use does not necessarily signify passive voice. By all means seek and destroy as many incidences of the verb 'To Be' as you can, but do it because using an action verb leads to more dynamic writing, not because someone told you it's 'passive voice'.
This public service announcement was brought to you by the verb 'To Be' and the letters P, M and S. Thank you.