1 . Put on your hiking boots and explore islands with waterfalls and active_________(火山) .（根据汉语提示单词拼写)

2 . Having studied ______(火山) now for many years, I am still amazed at their beauty as well as their potential to cause great damage. (根据汉语意思单词拼写)

3 . All the ___________（火山）in the country erupted ten times last year, killing about 800 people. （根据汉语提示单词拼写）