Should you speak to adults like you speak to your friends?

It depends on who the adult is and what your relationship with said adult is. If they're for example a teacher, doctor, or stranger then no you treat them with more respect and you should be more formal. If it's a parent or a family friend then it's ok to be a little looser.

a, a knight

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.