He took off at once and headed back to the motel.他立刻离开，回到汽车旅馆。Remove from the heat, add the parsley, toss and serve at once.端离炉子，加上欧芹，颠起翻面后就立刻上桌。I wrote back to Meudon at once to fix up a meeting.我马上给缪顿回信安排会面。...
at once的近义词有：immediately, instantly, presently, directly, shortly, soon, at once, right away。下面这些副词或副词词组均有"立刻，马上"的含义：immediately：指做完一件事后，立即就做另一件事，中间一般没有明显的时间间隔。instantly：指恰恰就在此刻，一秒钟也没耽误。presently：指不久、即将。directly和immediat...