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: ( CNN ) On April 20 , 2010 , a final cement seal of an oil well in the Gulf of Mexico failed , causing what has been called the worst environmental disaster in U.S . history and taking the lives of 11 rig workers . 2: The federal government estimated 4.2 million barrels of oil spilled into the Gulf , but BP argued in court that it was much lower . 3: April 20 marks 5 years since the BP oil spill .

1: oil 2: oil 3: oil