The adverb is either because it helps describe the sentence more.
Perhaps he meant that they both understood what the other character or thing was saying, without saying a word
Answer: Think about the question from your own life - which of these types of non-fiction resources do YOU use most often? Why is it useful to you? What makes you choose to use that type instead of one of the others?
Explanation: Answering those questions should give you your response, and then you'll just need to edit your grammar, spelling, capitalization, and punctuation.
