Hey,
Yep, you are right on point number 3. Stylistically speaking, we sometimes use the passive voice on purpose if you want to deny responsibility for something. For example, we might say "mistakes were made" rather than "he made a mistake" because it is less direct and accusatory. For the GMAT, though, I would steer away from it.
In terms of passive voice sentences with "by", you can see it with the Active-Passive versions of sentences below.
I like her - She is liked by me
The chicken crossed the road - The road was crossed by the chicken
I live in China - China is lived in by me
Thanks jonnyh,
I understood this one, but i get lost when i try to arrive at general rule for passive identification. Please read below patiently to understand confused state of my mind when it comes to passive identification
1. "There was/is/were" as you mentioned would make the subject of sentence to function as object and hence the sentence would become passive. Correct ?
2. You mentioned "By" makes sentence passive.. can you give an example..
3. Also i high school i learned a general rule,
A did B = active
B was done by A = passive