1 . Sailing is one of the most fun and exciting ways to enjoy the world’s great bodies of water. You can sail wherever you find enough water and a little wind to navigate (导航) a boat.     1     Those with less spare time who are only looking for a fun way to relax can enjoy sailing near the shore on the closest body of water.

Sailboats come in all sizes.     2     Learning to sail will allow you to enjoy the water year-round, since you can still sail when the water becomes too cold to swim or water-ski. The art of sailing will open your eyes to a whole new world of water sports.

    3     You control the boat by using a rudder (船舵) and sometimes other more complicated skills. Through the management of the sails, a sailor can control the force of the wind in them, which can change the direction and speed of the boat.

Sailing is a rather complex art.     4     Before you begin, you will need to become familiar with the parts of the sailboat. You must be able to swim well and you need to know first aid, so you are prepared if there is an emergency. Then you need to learn the basics of sailing, such as judging the wind, understanding the conditions of the water, and knowing how to handle the boat.

Sailing is an amazing way to stretch (拓宽) your boundaries. You will find new ways to enjoy water sports from the deck of a boat.     5    

3 . Roller coasters are fast and exciting. But passing a painful kidney (肾) stones is not. The process is painful and can take a long time. But American researchers have found that a roller coaster ride just might help those suffering from a kidney stone. They say such rides help patients pass the stones with a 70 percent success rate.

David Wartinger led the study. He found that where the person sits on the roller coaster can make a big difference. He said, “In the pilot study, sitting in the last car of the roller coaster showed about a 64 percent passage rate. Sitting in the first few cars only had a 16 percent success rate.”

It also mattered where the stones were located in the kidney. The researchers found that stones located in the upper part of the kidney model were passed 100 percent.

When it comes to passing kidney stones, not all roller coasters are equal. The researchers used 174 kidney stones of differing shapes, sizes and weights to see if each model worked on the same ride and on two other roller coasters. They found that Big Thunder Mountain was the only one that worked. The other two roller coasters both failed the test. Wartinger said the other rides were too fast and too violent. The movement forced the stones against the side of the kidney. He said that the ideal roller coaster is rough and quick with some twists and turns.

Wartinger thinks roller coaster rides could also be used as a preventative measure. He said that a yearly ride on a roller coaster could even prevent stones from developing. “You need to heed the warnings before going on a roller coaster,” he said. “If you have a kidney stone, but are otherwise healthy and meet the requirements of the ride, patients should try it.”

He adds that it’s definitely a lower cost alternative to other treatments. And riding a roller coaster is definitely more fun!