English greetings

These usages you said are all in Chinese, so it is impossible to translate them simply.

You can simply say hello. Or hey! Do it.

In Britain, you can talk about the weather with your neighbors, for example, say hello. Nice day, isn't it? The weather is really good ~

Many customs in Britain are different from those in China, but don't say things like "come back" and "go out", which will make them feel puzzled and even think that you are interfering in their lives.

As for your last sentence. It's not too much to say this.

Just a moment, please. Just a moment, please.