
Victor S. answered 04/04/19
Guiding students to college, test prep and ADHD success since 2007
You're reading one of the best (and thinnest) books on writing English! I found the section you're referring to: rule #10, Use the active voice, on page 35. (My book is the classic edition, edited by De A'Morelli).
First, let's define the active voice as an order of three elements: S V O
The subject does the verb to the object.
Note, we may not always have an object, but most of the sentences in this book's section do.
The ideal way to compose most sentences is the active voice.
Next, let's define what the "subject of a passive construction" is.
Let's look at the first example sentence (with the X mark to indicate it is flawed) in the book:
'A survey of this region was made in 1900.'
I suggest first marking the Subject and Verb.
Subject: A survey of this region
Verb: was made
Does the subject "express the entire action?"
Yes, because the Region was the noun that was Surveyed.
The original subject (a survey of this region) should be rewritten as the noun that was acted upon:
The Region was Surveyed.
The problem with the original sentence is that following "A survey of this region" is the verb* "was made" which completes the sentence but does not involve the true subject (region) and verb (surveyed).
Tip: avoid constructing a sentence that involves a verb (surveyed) that is not the actual verb of the sentence. This ends up with a verb near the end of the sentence (was made).
*The verb "was made" is two words, but I call it the single verb because it is a perfect past tense form.
Improved sentence: "This region was surveyed in 1900."
We eliminate "was made."
Second example: "Mobilization of the army was rapidly effected."
Clue: the last word is a verb.
Verb: what is the important verb that appears in this subject?
"mobilization"
Fix: convert the original subject "Mobilization of the army" into a noun and verb:
"The army was mobilized"
Complete the sentence with the important information from the original: "rapidly effected."
Improved: "The army was rapidly mobilized."
This is the last example in the book. See how you rewrite it:
"Confirmation of these reports cannot be obtained."
:)