Sigma
[计] 求和\\n[医] σ(希腊文第十八个字母)
🗣️ 情景例句
Oh, it's so exciting, isn't it, Richard?
噢 ，这太令人兴奋了 ，是不是 ，Richard？
We shall never have friends if we expect to find them without fault.
指望朋友无缺点，永远休想交朋友。
I've live here for twenty years.
我在这里住了20年了。