We don't have to worry about the philosophical questions of comprehension to find cases like this present challenges. These types of example (better articulated in mrec's link) are cases where we can imagine straightforward, plausible queries that the computer would be unable to answer: "what shattered?" or "what remains?" Some of the examples are such that simple web searches wouldn't be helpful in resolving the ambiguity; you'd need some "common knowledge." (Again: not that that's an insurmountable or necessarily relevant problem.)