once
at once
意：马上;立即;立刻
例，Go away at once?
马上滚开!
I want you to carne at once !
我要你立刻就来!
I knew at once what he meant.
我马上就明白了他指的是什么。
Once again
用：也说Once more!Repeat!
意：再说(读、唱一)一遍!再来一次!
例： Naw, children, once again, I loveP eace..."
好，孩子们，我们再唱一遍:“我爱和平…”
A: OK, now, say, Bnn jour.
好。来说“Bon jour".,
B: Ban jour!
Bon jour!
A: Gnce again!
再来一遍!
once or twice
意：一两次;几回;偶尔
例:Harre you ever been to Sydney?
你去过悉尼吗?
B: I've only been there once or twice.
只去过一两次。
