directly

Compared meaning: without any delay (adverb).

比较义项：立刻，毫不迟延（副词）。

• now

  The most casual, everyday word for acting at once; often paired with 'right' for emphasis and common in urgent commands or requests.

  这是表示立刻行动最口语、最常用的词，常与right搭配加强语气，多见于催促或紧急的命令句中。

  Stop arguing and get in the car now!

  别再吵了，现在就上车！

• directly 本词

  Chiefly British and slightly formal or old-fashioned for 'immediately'; it can also mean 'in a straight line', a separate sense not compared here.

  在这个意思上比较偏英式英语，语气略显正式或老派；directly也可以表示「沿直线」，那是另一个不在此比较的意思。

  I have to finish this call, but I will be with you directly.

  我得先讲完这通电话，但我马上就会过来陪你。

• immediately

  The neutral, most common word for 'without any delay', natural in both spoken and written, formal and informal English.

  是表示「毫不迟延」最中性、最常用的词，口语和书面语中都适用，不带特别的地域或正式色彩。

  She immediately apologized when she realized her mistake.

  她一意识到自己的错误，就立刻道歉了。

All three mean without delay. Now is casual, often paired with 'right', common in commands. Directly is chiefly British, formal or old-fashioned. Immediately is the neutral, most common word, natural in speech and writing. Directly can mean 'in a straight line'; not compared here.

这三个词都表示「立刻、毫不迟延」，但语气和使用场合有别：now最口语化，常与right连用表示强调，也常见于催促的命令句；immediately是最中性、最通用的说法，书面和口语皆可；directly在这个意思上略显英式和正式，日常口语中不如另外两词常用。这里不比较directly「沿直线、径直向前」的意思，也不比较now表示「现在（此刻）」这一更宽泛的时间概念。