Walla
n. 经办业务人；要人（等于wallah）
🗣️ 情景例句
Are you being waited on?
您需要服务吗？
We may be able to help you in some way.
我们也许能在某些方面帮助你。
Ethanol is more effective at a concentration of 50-70 percent;
乙醇的浓度为50％至70％时比较有效，