take up (time)

To "take up" something means to use it. This phrasal verb is most often used with "space" and "time":

It takes up too much space.

Having kids takes up almost all of your free time.

This would not work with something like a tool. "Can I take up your hammer?" would be incorrect, for example.

Listen, (sentence)

When you start off a conversation with "Listen", it seems that you want to get to the main point of the conversation quickly. You use it like this:

Listen, I know that we've had disagreements in the past, but I hope that we can work together on this.

Listen, we don't have much time, so let me explain what happened.

There are also other reasons to start off a conversation with "Listen" as well, such as when you're giving advice or when you're introducing an uncomfortable topic.

I don't want to take up too much of your time.

You can use the phrase "I don't want to take up too much of your time" at the beginning of a conversation, to show that the conversation is going to be short:

Hey, Melanie, I don't want to take up too much of your time, but I need to go over these sales projections with you. Do you have a second?

You can also use this phrase to end a conversation politely, in the same way as the similar phrase "I don't want to take up any more of your time":

Listen, I don't want to take up too much of your time, but it was great talking to you.