Licenses

[Sama34]

Licenses are a PITA when you don't understand them (lol) and being a non-native English speaker doesn't make things easier either.

May somebody (try to) answer this?:
Can I use GPLv3 code in LGPL sofware maintaining the LGPL license, if so, how?
Apache License v2 seems to be GPLv3 compatible. If I do want to write plugin that uses code under the Apache license, what are the requirements fo it? Do i have to add a line before each code stating I took it from a Apache licensed software?

Lets say I write a function, function();, I have it coded and pasted in a .txt file in my desktop. Today I copy it and paste it in a GPLv3 licensed script, can I copy it tomorrow from the .txt file and paste it in a non-free script?

Very confusing when I do like releasing plugins and sometimes I do want to modify other free plugins to no write my own code ¬_¬

.. If I modify a Apache 2.0 licensed script can I released it under the same license with no problems?

I do use the GPLv3 license when I use other people code (control_object(); ), I don't mind. But when it comes to inserting GPLv3 code in a plugin that is not meant to be all free, or when I want to edit a plugin under the Apace 2.0 license, that is GPLv3 compatible, it is a pain to understand all of this...

Hopefully somebody here knows about this matter :-/