每日口說挑戰氫氣、氧氣、二氧化碳、氨氣和氯氣的測試｜化學之旅 (Testing for Hydrogen, Oxygen, Carbon Dioxide, Ammonia and Chlorine | The Chemistry Journey)

聽聽句子怎麼說

We test for gases in the laboratory because it is nearly impossible to determine the identity of a gas just by its appearance.

我們之所以會在實驗室檢測氣體存在，是因為單憑外表幾乎不可能判定氣體種類。