询问与解释科学现象 — 英语填空题
题目
Complete the dialogue with the correct words. — Ken: ___ does the candle go out after we cover it with a glass jar? — Ann: Because the flame uses up the ___ inside the jar, and fire cannot burn without it. (第一个空选填 Why/When，第二个空填一种维持燃烧的气体，用英文名称作答)