This worksheet is about a video from National Geographic about UFO's, it is useful to practice the listening skill and it contains general and specific information, students can discriminate between similar words and work out with prefixes. It is a lesson for 1 hour and 15 minutes and it is advisable for elementary and pre-intermediate students. I cut the original video in order to make it short. So here you have the whole video, but the lesson is only up to 2:45.