题目内容：

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

Floating mountains in the ocean are better known as icebergs (冰山). Icebergs are 1. (mass) of freshwater ice that have broken from a glacier (冰川) or polar ice sheet. Most icebergs are formed around Antarctica and Greenland.

Icebergs 2. (see) today began thousands and thousands of years ago. They began as flakes of snow falling on land. Over the years, more and more snow fell. The snow on 3.bottom was crushed (压碎) because snow on top was packing it down. Years of 4.(melt) and freezing formed layers of ice thousands of feet thick. These sheets of ice are called glaciers. During the warmer weather in spring 5. summer, pieces of ice break off from glaciers. The broken pieces of ice fall into the water and become icebergs.

Icebergs vary 6. size. The largest iceberg ever recorded was the size of the state ofRhode Island in the United States. The 7. (tall) iceberg stood 550 feet above the ocean. That’s about the size of the Washington Monument in Washington, D. C.

Icebergs can be very 8. (danger) to ships traveling near them because only one-eighth of an iceberg 9. (be) above water. This means that the rock-hard ice is much larger underneath. Captains taking 10.(they) ships around an iceberg may miscalculate the size of the iceberg.