Umer
abbr. unit mass emission rates 单位质量发射率
🗣️ 情景例句
Is that all?
就这些吗？
How long have you been married?
你们结婚多久了？
If they knew how difficult it was to drill through the hard rock, they would lose heart.
如果他们知道了钻透那坚硬的岩石有多么困难，他们会丧失信心的。