Skin--diving (  ) is a new sport today . This sport can take you to a wonderful world . It's like to visit the moon . When you're under the water, it's easy for you to climb big rocks (  ) because you're not heavy. Here, under the water , everything is blue and green . During the day , there's enough light . And you can see a lot of fish swimming around you. You can catch them with your hands. To catch fish is of the most interesting parts of this sport . When you have tanks (  ) of air on your back , you can stay in deep water for a long time . But you must be careful when you dive in deep water . With a tank of air on your back, you can   _   .
not move any more stay under water for a long time catch fish very easily can only stay in deep water