一下 conveys the meaning of a bit, a little in the context of a verb that's not quantitative. In English we say come here for a bit, help me out a little. In equivalent Chinese usage: 帮忙 = to help => 帮一下忙 = help a little. 来 = to come => 来一下 = come for a bit. 休息 = to rest => 休息一下 = rest a bit If the verb is quantitative, like to drink, or to eat you would not use 一下, but instead 一点. 吃 = to eat => 吃一点 = eat a little

“一下”相当于“一次”的意思。比如，我用一下好吗？ = 我能用一用吗？ 我能用一次吗？

我觉得啄木大大鸟 的答案比较好！呃，好奇怪的名字，但蛮可爱！

一下：轻微的请求。比如：来一下，帮一下。 这词多用在口语中，而且是关系一般的同事或陌生人时候用的。 比“吧”的语气更请求一些。比如“来吧，帮我把”

Thanks all for your help.