must, have to, got to

Today we'll talk about things that you are obligated to do. You have no choice, you are required to do it. In those situations you can use the following verbs:

Must

This is very formal sounding and isn't really used in casual conversation.

I'm terribly sorry but I must be going.

Have to

This is a fairly standard verb used to talk about obligations.

I'm sorry but I have to go.

In more casual English you would say hafta.

I'm sorry but I hafta go.

I hafta clean my room, it's a real mess right now.

In the past tense, to talk about things you were obliged to do before, use had to.

I had to wear a uniform in high school.

If you want to sound more casual use had TA.

I had TA do my homework when I was a kid or I'd get in trouble.

Got to

Another verb with exactly the same meaning is got to.

I'm sorry but I got to go.

I got to work hard to realize my dreams.

In casual English, we say godda.

I godda call my Mom, it's her birthday today!

I think got to sounds slightly more friendly/casual than have to. It is also only used to talk about current obligations NOT things you had to do in the past.

Well, I godda go. I hafta get ready for work.

See you,

Phil