I have got to...
1. I've got to go.
2. I've got to buy something to drink.
3. I have got to mail some cards to my friends.
4. I've got to apologise for troubling you so much.
5. You've got to try this dish; it's tasty.
A: How many candy bars have you eaten today?
B: I think I've eaten ten so far.
A: That's too much! You've got to stop eating so much.
A: Because if you eat too much candy, you'll rot your teeth.
B: You're right. I've got to stop eating so many sweets.