阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
Tornadoes are one of nature's most (power) and destructive (破坏性的) forces. Here's some information on what a tornado is, how to prepare for one, and what to do if you (catch) in it.
A tornado is a violently rotating (旋转的) column of air that extends from a thunderstorm to the ground. It's often foreseen by a dark, greenish
sky. Black storm clouds gather. A funnel (漏斗) (sudden) appears, falling from a cloud. The funnel hits the ground and roars forward with a terrible sound. The tornado tears up everything in its path.
Tornadoes can be deadly, but there are steps you can take (reduce) the risk to you and your family. Here are some useful (tip) to keep in mind:
• Prepare for tornadoes by gathering emergency supplies, (include) food, water, medicines, batteries, flashlights, road maps, etc.
• When a tornado (approach), anyone in its path should take shelter indoors — preferably in a basement or first-floor room or hallway.
• Avoid windows seek additional protection by getting underneath large, solid pieces of furniture.
• Avoid automobiles and mobile homes, provide almost no protection from tornadoes.
• Those caught outside should lie flat in a depression or on other low ground and wait the storm to pass.