问答题
《复合题被拆开情况》 Coral reefs, sometimes called rainforests of the sea, make up only 0.1% of the ocean floor, but they are home of the world’s fish. Reefs grow in tropical waters. The largest is Australia’s Great Barrier Reef, which is over 1,200 miles long off the Queensland coast. Reefs are not only important for food; they are also valuable for tourism. For example, Florida’s reef is worth about $63 billion every year in tourism. Unfortunately, the consequences of increased human activity are damaging reefs around the world.
【正确答案】Clean, clear water.
【答案解析】文章第三段第一句提到,“珊瑚礁需要干净、清澈的水才能生存”。由此可知本题答案。