Use passive voice when you want to
a) emphasize who is responsible for an action
b) eliminate the verbiage in your writing
c) emphasize the receiver of the action
d) write a clearer sentence
Question 2
Two word groups to avoid in the beginning of a sentence are
a) There are and It is
b) I and You
c) personal pronouns and abstract nouns
d) any form of a verb with an auxiliary