Sigma
[计] 求和\\n[医] σ(希腊文第十八个字母)
🗣️ 情景例句
I'm worried, Philip.
我很担心， Philip。
Is it long drive from here to the dapartment store?
从这里到百货公司开车也要走很多时间。
Ships may be delayed by storms; flights may be cancelled because of bad weather, but trains must be on time.
轮船船期可能因风暴而推延，飞机航班可能因恶劣天气而取消，唯有火车必然是准点的。