题目

如图，将盛满氢气的．集气瓶瓶口朝下，同时把一根燃着的木条缓缓伸到瓶底，可观察到的现象是 ，再将其缓缓抽出，可观察到的现象是 该实验说明氢气具有的化学性质是 答案：【1】木条熄灭，瓶口有淡蓝色火焰【2】木条复燃【3】能燃烧但不能支持燃烧 A knock at the door again! It was the third time someone _________ me that evening. A. has interrupted                                             B. had interrupted        C. to have interrupted                                        D. would have interrupted