[话题设计] 有一个美国小孩子,一出生就一点免疫力也没有,科学家只能把他放在一个完全无菌的玻璃罩里生活。在这样的环境里,这孩子活了下来,一直长到11岁。因为一个很小的疏忽,外界的空气侵入到玻璃罩内,孩子被感染, [Topic Design] There is an American child who has no immunity at birth. Scientists can only put him in a completely sterile glass cover. In this environment, the child survived until he was eleven years old. Because of a small oversight, outside air intrudes into the glass and the child is infected.