2013年职称英语考试理工类题型概括大意习题4_第5页

　　 3　Ask your child to get a piece of string, some salt, a glass of water and an ice cube (冰块). Tell her to put the ice in the water, and then put one end of the string on the ice, leaving the other end over the side of the glass. Put a little salt on the ice. Wait a minute, and then pull the string; it should be attached to the ice. Ask the child: "what has happened?"

　　 A　the icebox
　　 D　the experiment
　　 F　water
　　 30 The experiment shows that salt changes the behavior of　　　　　　.