1.忽然,突然
2.突然
1.happening suddenly, usually when you are not expecting it
2.at the same time
3.very suddenly
1.Go grocery shopping once a week. You'll save money and time if you make the effort to plan for a week and to shop for it all at once.
一周去一次杂货店。在去购物前如果你能列出计划，在购物时一次买清将为你节省时间和钱。
2.But the boat changed into a dragon all at once! The dramatist dreaded it so much that he dared not to see it.
但船儿猛然间变成了一条龙剧作家非常恐惧，以至于不敢看它。
3.When my siblings and I were young adults and starting to ask lots of questions, our grandfather decided to educate us all at once.
当我们这些孩子刚长大，开始问许多问题时，外祖父决定把这些知识一古脑儿教给我们。
4.In this case, you might take a few days at a time rather than take one month all at once.
在这种情况下，你可以防几天假而不是一下子放假一个月。
5.It is how much page file space would be used if all the private committed virtual memory in the system had to be paged out all at once.
换言之，如果系统中所有的私有提交虚拟内存不得不一次性全部被换出去的话，将用到多少页面文件空间。
6.All at once sky was covered with dark clouds and less than a minute we were in a terrible storm.
突然天空乌云笼罩，不到一分钟，我们就被卷入了可怕的暴风雨中。
7.To me it sounds like doing lots of things all at once, only doing them all very badly and feeling like an exhausted failure when it's over.
对我来说，它听起来就像是要同时干很多件事情，只不过全都完成得不怎么样，而且做完之后只觉得筋疲力尽，失败透顶。
8.It is not easy to cope with electromagnetic shielding, sealing and cooling all at once in designing electronic cabinet.
同时满足屏蔽、密封和导热三个指标，是电子设备机箱设计的一大难题。
9.All at once it rushed from the dark borizon toward the ship with a frightening speed.
突然它以惊人的速度从黑色的地平线冲向船只。
10.Being idle, go angling at a green stream; All at once, I dream in a boat to the side of the sun.
闲来垂钓碧溪上，忽复乘舟梦日边。