一、阅读下面文段 ,完成 1— 6题。①海底大体上是平坦的 ,平均深度是四千米。也有峡谷和深渊 ,最深的地方达一万一千米。山脉也不少 ,在大西洋有大西洋山脉 ,在印度洋中央有印度洋山脉 ,在北极有罗蒙诺索夫山脉。不仅有一般的山脉 ,在太平洋还有海底火山。②海底的动物已经知 First, read the following paragraphs to complete the 1 - 6 questions. 1 The sea floor is generally flat with an average depth of four kilometers. There are also canyons and abysses, and the deepest places reach 11,000 kilometers. There are also many mountains, the Atlantic Ocean in the Atlantic Ocean, the Indian Ocean Mountains in the middle of the Indian Ocean, and the Lomonosov Mountains in the Arctic. There are not only general mountains, but submarine volcanoes in the Pacific Ocean. 2 Undersea animals have been known