【Manypeoplelikediving（跳水）inwaterbecausetheycanexplore（探险）theunderwaterworld．Butthereisanotherkindofdiving，somepeoplediveinthesky!Thisisreallyaveryexcitingsport．Askydivergoeshighupintheairona】

　　Many people like diving（跳水） in water because they can explore（探险） the underwater world．But there is another kind of diving，some people dive in the sky!This is really a very exciting sport．A skydiver goes high up in the air on a plane．Then he jumps off the plane and floatsC漂浮）in the air with the help of a parachute．A parachute is like a huge umbrella，it is put on the back of the skydiver．When the skydiver reaches a certain height，he will pull a string（绳子） and the parachute will open up in seconds and carry him gentle down to the ground．Skydivers like doing a lot of fantastic tricks in the air．After jumping off the planes one after another，they will try to stay in the air and hold each other's hands．They can form different shapes．

　　Is it safe to do skydiving？Yes，if we receive proper training．But sometimes，accidents do happen．In Canada，two skydivers were killed in 1991when they jumped off the plane but their parachutes got tied up （缠住）each other．The parachutes could not open up and both crashed down and died．

　　66．Why do people like diving in water？___

　　67．How does a skydiver go up into the sky？___

　　68．Is a parachute like an umbrella？___

　　69．What will a skydiver do to open his parachute？___

　　70．Is it always safe to do skydiving？___．