Other forms: covers a lot of ground; covered a lot of ground; covering a lot of ground
If you cover a lot of ground, you either travel quite a distance or deal with a large amount of information on a wide range of topics. An art history seminar that includes 18th-century art through modern digital media covers a lot of ground.
The idiom cover a lot of ground itself covers a lot of ground: It can be used to describe progress through physical space or conceptual material. A baseball center fielder who sprints long distances to catch fly balls is often described as covering a lot of ground. If your vehicle gets great gas mileage, you will be able to cover a lot of ground on a trip before you have to fill up the tank. At a study session to review for a final exam, you'll probably need to cover a lot of ground.