Methanophone
瓦斯警报器
🗣️ 情景例句
Have you ever been to Niagra Falls?
你去过尼亚拉加瀑布吗？
You have a younger brother, don't you?
你有个弟弟，是吗？
Sometimes the secrecy goes to such an extent that the whole nature of the research cannot be mentioned.
有时，保密竟达到了这样的程度，即连研究工作的整个性质都不准提及。