[填空题]The volcano in the cornfield grew until it was bigger than the cornfield! (41)______ People called the volcano the Little Monster because it grew so fast. Scientists came from all over the world to study it and watch it grow. It is not often that people get a chance to watch a volcano from the very beginning.
Most of the volcanoes have been here for a very long time. Some have been here so long that now they are cold. They are called dead volcanoes. They have stopped throwing out fire and melted rock and smoke. It is safe to walk on them. Farms are plowed on the quiet slopes, and people have built houses there.
Some volcanoes have stopped throwing out hot rock, but they still smoke a little now and then. They are "sleeping" volcanoes. Sometime they may "wake up".
(42)______.
Today volcanoes are not so dangerous for people as they were a long time ago. Now we know more about why volcanoes do what they do, and we can usually tell when they are going to do it. (43)____