Sigma bond
[化] σ键
🧩 词语组成解析
[计] 求和\\n[医] σ(希腊文第十八个字母)
🗣️ 情景例句
But first, I think we should take a moment
不过首先 我想我们应该用一两分钟
Saying is one thing, and doing another.
说是一回事，做是另一回事。
Bleriot set off half an hour later.
半小时后便正式出发了。