Definition: You will be given three sentences. Read them, then identify a noun phrase (person, place, or thing) or event that is shared between all three sentences. As the output, write the span of the text corresponding to that phrase in each sentence. Keep the order of the sentences, that is, your answer should look like: 1: *a phras from sentence 1e* 2: *a phras from sentence 2* 3: *a phrase from sentence 3*
Input: 1: Another U.S . official had said earlier that  some serious issues remain unresolved .  2:  It is still totally unclear when this might happen , if it happens at all .  3: U.S. official :  It is still totally unclear when this might happen , if it happens at all 

1: remain unresolved 2: is still totally unclear 3: is still totally unclear