阅读理解

     In England, everybody knows Jamie Oliver. He has his own TV programs. In these programs, he tells people how to cook healthy food. Everyone likes Jamie's programs because his food is easy to make.
     Jamie wants people to eat healthily. In some schools in England, the food at lunch time was't healthy. One day, Jamie went to a school to make a TV program about healthy diet. He cooked the food with lots of fruit and vegetables. At first the children didn't want to eat because they didn't like fruit or vegetables. But after they tasted the food, they started to enjoy it.
     Now the food for children in schools has become much healthier.

下列划线字解释全对的一项（    ）

如图所示，用10N的水平拉力F拉滑轮，使足够长的物体A以0.2m/s的速度在水平地面上匀速运动，弹簧测力计的示数为3N．若不计滑轮重、弹簧测力计重、绳重和滑轮摩擦，则下列说法中正确的有（　　）