They eat them. This has to do with your natural understanding of phrasing. In a sentence, phrasing tells you where the speaker is at the moment, where he is going, and if he is finished or not. Notice that the intonation stays on the nouns. Statement Stress the nouns and let the tone fall at the end of the sentence.
Dogs eat bones.
An extremely important part of intonation is compound nouns and complex verb tenses . Once the intonation of new information is established, you'll soon notice that there is a pattern that breaks that flow. When you want to emphasize one thing over another, you reflect this contrast with pitch change. Bob studies English . Bob studies English, but he doesn't use it.