When reading a memoir, how can a person recognize themes the author explores?

by asking a teacher or classmate for assistance
by noting the publisher information inside the front cover
by looking for facts and opinions that repeatedly show up
by creating a list of unfamiliar words from the memoir

When reading a memoir, a person can recognize the themes the author explores by looking for facts and opinions that repeatedly show up. If they occur over and over again throughout a memoir, it is likely that these memories are quite important to the author and that he wants you to pay attention to them as well. A teacher or a classmate can help you, as well as the other option (except the last one), but it is best to try and figure this out on your own.

Walked would be the participle here. as it is a verb ending in -ed.