Read the paragraph. Then answer the questions below. (1) The Panama Canal changed ocean travel for people and goods. (2) The American-built canal connected the Atlantic and Pacific Oceans. (3) Ships no longer needed to go all the way around South America. (4) Instead, they could take a shortcut through the Panama Canal. (5) Before the canal was finished in 1914, an ocean trip from California to New York took 60 days. (6) Thousands of ships cross this “seventh wonder of the modern world” every year. (7) The trip was 13,000 miles long. (8) Passing through the Panama Canal, the trip is shortened by about 7,000 miles and 30 days. (以下问题答案用段落里每句前的数字写进相应的空格中) 1. Which sentence in the paragraph is the topic sentence? 2. Which sentence is the concluding sentence and should be moved to the end of the paragraph?