题目

In the United States, 30 percent of the adult population has a weight problem. To many people, the cause is obvious: we eat too much. But scientific evidence does little to support this idea. Going back to the America of 1910, we find that people were leaner than today, yet they ate more food. In those days people worked hard physically, walked more, used machines much less, and didn’t watch television. Several modern studies, moreover, have shown that fatter people do not eat more on the average than thinner people. In fact, some investigations, such as a 1979 study of 3,545 London of写出下列单词的现在分词。1. sing______     2. sit______         3. play______4. have______    5. laugh______    6. read______