Gordon is at once modest and clever.
（誤譯）戈等立即顯得聰明和謙遜。
（正譯）戈登既聰明又謙遜。

1. at once 馬上，立刻

We agreed on starting at once.
我們一致同意立即出發。

The police decided to move at once.
警察決定立即采取行動。

Better deny at once than promise long.
與其長期許諾，還不如立即拒絕。

2. at once 同時

Qubits are able to exist as both 0 and 1 at once.
量子位元能同時以0與1的狀態存在。

That's a disadvantage when you're cooking several things at once.
如果同時要烹飪幾件時這是一個缺點。

Bill can play the piano , sing and lead his orchestra all at once.
比爾能夠同時彈鋼琴、唱歌和領導他的管弦樂隊。

意思相近的短語：

1. on the spot 立刻，當場；在危險中；處于負責地位

We are a bit on the spot here.
我們這里有點麻煩。

He would invent fanciful names on the spot.
他會當場發明出一些怪誕的名稱。

That would put the administration on the spot.
這將讓政府陷入困境。

2. in a snap 馬上，立刻

Easily upload your video to the web in a snap!
輕松上傳你的視頻，該網站要在瞬間完成！

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

In a snap, the song information will appear on the screen.
很快這個歌曲信息將顯示在屏幕上。

3. in a heartbeat 馬上；立刻

If i were you, I'd divorce him in a heartbeat.
如果我是你，我會毫不猶豫地跟他離婚。

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

These things happen quickly on-screen, with the years elapsing in a heartbeat.
種種因果在銀幕上飛快掠過，而一年年的歲月以心跳的速度流逝著。