Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) Temporary barriers appeared to prevent serious flooding Tuesday in Iowa's second-largest city, but officials are warning thousands of evacuated Cedar Rapids residents to stay away for a couple more days. "It's not time yet to go back to life as usual, but we're getting close," City Manager Jeff Pomeranz told reporters late Tuesday morning after the Cedar River crested there just above 22 feet -- 6 feet above what is considered major flood stage. "It's not over yet, but we're feeling very good ... that this temporary system that we built" will protect the city of more than 120,000 people, Pomeranz said.More than 10,000 residents have evacuatedIowa's National Guard has deployed more than 400 soldiers 
 Question:_ city workers, contractors, volunteers and National Guard troops had hastily erected a system of temporary walls, levees and 250,000 sandbags around the city over the weekend -- and it appeared to be holding, officials said Tuesday.

Cedar Rapids