Drones are being used by tech-savvy farmers to monitor and spray crops,by researchers to measure environmental pollution and by Hollywood studios to capture action-packed footage for blockbuster movies.Drones are even saving lives,as first responders to coordinate operations and search for missing hikers. And of course,drones are being flown by hundreds of thousands of amateurs.
Drones are used in a variety of f______.
【正确答案】：fields
