Sigma
[计] 求和\\n[医] σ(希腊文第十八个字母)
🗣️ 情景例句
I have no time for extra-curricular activities.
我可没时间参加课外活动。
What time are you going to get up tomorrow morning?
你将在明天早上什么时间起床？
Errors and uncertainties multiply, cascading upward through a chain of turbulent features,
错误和不可靠性上升，接踵而来的是一系列湍流的微状，