Active vs. Passive Voice

[D. Hailey]

I agree with the advice you have received so far.  A good mix of active and
passive voice is common in excellent writing.

Pinkham's rules of thumb are good, but for more complex sentences, find the
agent (the person or thing doing the action).  If the act proceeds the
agent, the sentence is usually passive.  

"After 100 years of safely sitting on that table, after a century of being
turned on and off every day without incident, the lamp was knocked off the
table and smashed by that the grandson of the prince."  

There are two simple questions: What was the act? And who committed it? Even
with the complexity of the sentence, it is clear that the agent (the
grandson) follows the action (breaking the lamp) in that sentence -- passive
construction.

If the agent is completely missing, and if the sentence is not a command
with an understood you, the sentence is also usually passive -- as any
4-year-old who has broken something knows. 

"The lamp got smashed to smithereens," said the little boy.  We are left to
wonder who did the breaking.

David E. Hailey, Jr., Ph.D.
Associate Professor -- Professional and Technical Writing
Utah State University
dhailey at english.usu.edu