【题文】 Scientists think that more than 1,500 volcanoes have erupted in the past 10,000 years. Mount Saint Helens, a volcano in Washington State, erupted in 1980. 【小题1】 Some volcanoes are on land. Many more volcanoes are under the ocean. Some of these volcanoes are underwater mount...
500volcanoes have erupted in the past 10, 000 years.Mount Saint Helens, a volcano in Washington State, erupted in 1980. 1Some volcanoes are on land. Many more volcanoes are under the ocean. Some of these volcanoes are underwater mountains. Some of these volcanoes are big cracks in the ...