The sentence that uses the passive voice for the main verb is: When we can pick our reading, mythology is most often chosen in my class. When a sentence is written in the passive voice, the subject becomes the receiver of the action. The subject in this sentence is "mythology" which receives the action of "most often chosen".
In my opinion, it is true because McCandless got ready for the trip by packing elementary things, opposed to the things we pack nowadays where technology absorbs much of our attention and time.
Through this quote, the author implies that today's society has limited our sense of freedom and adventure due to the increased use of technological devices which have become the new way to enjoy and be encased in a virtual world at the same time. In the past, children enjoyed more freedom and used to engage in more fun and adventurous games, rather than virtual ones as it happens at present time.
I will spray all the walls of my house when I paint it.
