In Klingon, the prefixes contain information about both the subject (who is doing the action) and the object (who the action is done to). The prefix bI- indicates that "you" are doing the action, but that there is no subject receiving the action. bISop "You eat (but not any specific thing)." The prefix Da- indicates that "you" are doing the action and doing it to something (but not to "me" or "us"). Soj DaSop "You eat food." By the way, the prefix for "you" doing something to "me" is cho- and for "you" doing something to "us" is ju-.
An explanation is given in the Tips & Notes. It’s a lot of new information and some details are bound to slip through the memory. But since Duolingo has hidden the Tips & Notes I want to make sure you know about them and where to find them. If you have not been reading the Tips & Notes, I would like to ask that you review those so we don’t have to continuously repeat the information that we have explained there.
If you are doing the course on iOS or Android, you cannot currently access the Tips & Notes through the app. To access the Tips & Notes, you will have to access the course using a web browser at https://www.duolingo.com/. You can still do it on your mobile device, but you will have to use the web browser instead of the app (or you can do it from a computer). When you click on a Skill, it will expand to reveal a Start button, a key, and a light bulb.
If you click on the light bulb it will reveal the Tips & Notes and give you a detailed explanation of the grammar that is introduced in that Skill. If you have questions after reading the Tips & Notes for any Skills, then please return to the forum to ask your question, explaining what you didn’t understand or what seems contradictory to you.