go straight (to somewhere)

To "go straight to" somewhere means going there directly, without going anywere else on the way:

I went straight to the hospital to see her as soon as I heard about the accident.

go to sleep

When you're talking about sleeping, there are several stages:

• When you're awake and then start sleeping, it's called "going to sleep".
• After you have gone to sleep, we say that you "are asleep".
• Then you "wake up".
• Once you wake up, you "are awake".

There are other actions that have similar stages. For example, you "put on" clothes, then "wear" them, then "take them off".

If you don't (do something), (consequence)

This is an expression that English speakers use when they need to threaten someone.

For example,

If you don't pay me by the end of the month, I'm kicking you out.

If you don't stop making that noise, I'm going to scream!

Of course, threatening people is often a bad idea and can lead to arguments.

behave yourself

"Behaving yourself" means acting in the way that you're supposed to.

We often tell children to behave themselves. This means that they should not:

make loud, annoying noises

move or run around too much

say rude things

Do you understand me?

When someone like a parent, teacher, or boss is angry, they may tell their children, student, or employee what to do, and then ask "Do you understand me?" They expect a response like this:

A: You are not allowed to go out with him again. Do you understand me?

B: (Looks angry.)

A: I said, "Do you understand me?"

B: Yes, I get it.

When English speakers ask "Do you understand?" or "Do you understand me?" it often sounds angry and impatient. If you want to know whether someone understands you, but want to ask politely, ask:

Does that make sense?

Or maybe:

Got it?