Copula
n. 系词, 介体, 接合部\\n[医] 介体; (舌)联桁; 交配
✅ 同义词
📖 牛津释义
copula
n
(grammar) type of verb that connects a subject with its complement 系词（即连系动词, 用以连结主语及其补语）
In `George became ill', the verb `became' is a copula. 在Georgebecameill一句中, became是系词.
🗣️ 情景例句
Rotten weather, isn't it?
天气糟透了， 不是吗？
When an opportunity is neglected,it never comes back to you.
机不可失，时不再来；机会一过，永不再来。
I'm not sure I can do it.
恐怕这事我干不了。