题目

完形填空 We have all heard of giant pandas, and know that they are endangered. When one has babies, it makes national news1and pictures of their babies are2 circulated. But it now seems that the giant panda is not 3 of itself. The lovely animals have 4 a classic test of self-awareness. They cannot5 themselves in the mirror. Researchers use the mirror recognition test to 6 whether children or animals have a7 of self-awareness. In the test, an animal is presented 8 a mirror. Researchers then watch to see 9 it notices a mark on its face, which is only10 in the mirror. If the animal notices th [创新]把电阻R1和R2与一个电源、一个小灯泡、一个开关和若干导线组成串联电路，接通电路后，如果小灯泡越亮，说明连入的电阻越小，请说出这种判断的依据．这种根据灯泡的亮度比较电阻大小的方法存在什么不足？请添加一个实验器材进行改进并说明改进过程及比较电阻大小的方法．