1. (To visit, visit, visiting) a national park can(to be, be, being) a wonderful way of (to spend, spend, spending) a day , but are these parks worthwhile or do they have too many drawbacks?
2. In addition, national parks make it possible for animals to have more space and freedom than they can (to have, have, having) in zoos and allow children to see animals (to wander, wander, wandering) freely instead of (to live, live, living) behind bars.
3. However, some people object to (to keep, keep, keeping) animals in national parks.
4. They believe that animals should (to live, live, living) in their natural habitats and shouldn't be used as a form of entertainment for visitors to these parks.
5. All in all, it would (to appear, appear, appearing) that national parks do have some advantages, but there are also several drawbacks to (to keep, keep,keeping) animals in them.
6. Perhaps it is time we started (worked, work, working) to protect animals in their natural environments.