Disasters(灾难) can happen when people fly a drone(无人驾驶飞机) without knowing how to really control it. A drone flying into an airspace could cause a great disaster if it hit a jet plane. Some have become tangled(缠结) in power lines, costing thousands of dollars to get them down. If people try to remove the drone themselves, they could be killed by electricity(电). A falling drone can do great damage（毁坏）to buildings and people.
One terrible accident happened when an operator lost control of a drone. The drone pilot was flying it by his home when its rotors(螺旋桨) hit a tree. The drone went out of control, falling into a neighbor's yard where a young child was playing. Sadly, this little boy lost his sight in one eye.
While drones can be harmful（有害的）, they can also be very helpful. At a sports event, drones can be used to give people a view from above or help coaches see how their players are doing. They are also becoming a useful tool for firefighters, helping them notice wildfires. Drones can closely watch populations of animals in the wild, especially endangered ones. In some very far-away places in the world, drones are the fastest way to take medicine to people who need it.
After the Nepal earthquake, the sky was filled with drones. They were fitted with cameras and their role was to fly over roads blocked by landslides to find people who are hurt or record any damage to bridges or buildings. The photos provided important information.
Some people think drones should be only used by governments(政府) to help when needed. Others think that as long as the rules are followed, there should be little risk to people. Drone makers say drones are exciting new technology and the future will be dominated(主导)by them.
