C4
abbr. 补体4（complement 4）
🗣️ 情景例句
I'm very proud of you. You really did a beautiful job.
我真以你为傲。你真的拍得很漂亮。
Here's no necessary.
我看没这必要。
I was born on Febuary 18, 1981.
我是1981年2月18日生的。