Gordon is at once modest and clever.
（误译）戈等立即显得聪明和谦逊。
（正译）戈登既聪明又谦逊。

1. at once 马上，立刻

We agreed on starting at once.
我们一致同意立即出发。

The police decided to move at once.
警察决定立即采取行动。

Better deny at once than promise long.
与其长期许诺，还不如立即拒绝。

2. at once 同时

Qubits are able to exist as both 0 and 1 at once.
量子位元能同时以0与1的状态存在。

That's a disadvantage when you're cooking several things at once.
如果同时要烹饪几件时这是一个缺点。

Bill can play the piano , sing and lead his orchestra all at once.
比尔能够同时弹钢琴、唱歌和领导他的管弦乐队。

意思相近的短语：

1. on the spot 立刻，当场；在危险中；处于负责地位

We are a bit on the spot here.
我们这里有点麻烦。

He would invent fanciful names on the spot.
他会当场发明出一些怪诞的名称。

That would put the administration on the spot.
这将让政府陷入困境。

2. in a snap 马上，立刻

Easily upload your video to the web in a snap!
轻松上传你的视频，该网站要在瞬间完成！

Not with a genius like me. I can get this done in a snap.
像我这样的天才是不必的。我只要一下子就搞定了。

In a snap, the song information will appear on the screen.
很快这个歌曲信息将显示在屏幕上。

3. in a heartbeat 马上；立刻

If i were you, I'd divorce him in a heartbeat.
如果我是你，我会毫不犹豫地跟他离婚。

What do you mean: wait? I could kill you in a heartbeat if I wanted to.
“等等”是什么意思？要知道我可以不费吹灰之力就杀掉你。

These things happen quickly on-screen, with the years elapsing in a heartbeat.
种种因果在银幕上飞快掠过，而一年年的岁月以心跳的速度流逝着。