I'll leave you be.

你继续忙吧。（类似于“打扰了”，“告辞了”。）

I'm off.

我走了。

例句：

- Well, it's been a great party. Good-bye. Got to go.

派对很棒，我要走了，再见。

- I'm off too. Bye.

我也走了。拜拜。

I've got to dash.

我得闪了。（英国人常说。）