Sigma.
[医] 千分之一秒
🗣️ 情景例句
About fifteen minutes.
大约十五分钟吧。
The packing must be strong enough to withstand rough handing.
包装必须很坚固，能承受野蛮装卸。
They were puzzled by several things.
有几件事情使他们感到迷惑不解。