ph.

1. He left on the instant.
他马上便走了。

1. 立即：on the inside 在里面 | on the instant 立即 | on the jig 战战兢兢地

2. 立即,马上：in an instant 立刻,瞬间 | on the instant 立即,马上 | on occasion 间或;随时

3. (马上)：on a winter morning, on Christmas Day, on night shift, on one's birthday, on schedule(按时... | on Sunday, on that date, on the eve of, on the following day, on the instant(马上), | on the moment(立刻),

4. 立刻：for an instant 瞬间;片刻 | on the instant 立刻 | with the intention of ... 以...为目的