Yes, you can, just know the first one is super informal and should only be used with friends.

There is no difference you can use both interchangably.

Irena is right, "gotta" is very casual and informal. Its a made up word used in pace of "got to". "You have to" is more more formal but can be used anywhere even informal settings because it's grammarically correct.

Saying "I don't care" mean you don't have an interest in something. It can be about anything. I usually sounds very rude though so be careful where you say it. To say "I don't matter" mean you don't value yourself. People will become worried if you say this because they will think you don't value or love yourself.

In America we use them interchangably most of the time. We really only use Café to sound fancier. So your friends will understand you whatever one you want to use. If you still help just think of coffee shops as bigger, more corprate places that are usually in malls, like Starbucks or Carribou Coffee. A cafe is smaller and usually not part of a big corprate chain and in smaller, less busy places. While some coffee shops offer some food, café are the ones that offer more varity as well as other drinks. If some used coffee shop and café in same sentence it they probably meant that it was a coffee shop that also sold food, tea, and other things.

The first time

This is my first time using italki.I know it from my QQ friends. They told me that there is a website to learn English. You can find the partners to learn from each other on it, and you can talk with a native English sperker to improve your speaking English and writing English. So I registered, and I hope to find the partners.

Thanks for your help.

Yes your correct. You would use it like this "She was born in the 80's" or "She was born after the 80's." But you can still use 1980 and 1990 and still sound natural!