at a time
每次, 一次
例句与用法：
Personal enmities must be forgotten at a time of national crisis.
民族危机当头，必须捐弃个人恩怨。
Such waste of money should be deprecated at a time like this.
在这种时候应大力反对如此浪费金钱。
He used to abandon his work for months at a time.
他过去每次放下工作就是几个月。
If only problems would come one at a time!
要是问题一次只发生一个该多好！
He tossed the peanuts into his mouth one at a time.
他每次将一粒花生扔进嘴里。
Female sheep produce one or two lambs at a time.
母羊一次生一到两只羊羔。
每次; 一次
Take three pills at a time.
每次服三粒。