why do we need to study english?

Ok that's good! can you tell me why/how you divvied them up like you did

Keep alive is something everyone should be doing... also reminds me of that Bee Gees song.
Keep cold is good because clearly everyone loves cold weather.
Keep beautiful puts a positive message upon everyone who reads it!
Keep quiet is grammatically correct, which gets extra points.
Keep rich also is great, because being wealthy is, like, good and stuff.
Keep free - has an underlying theme of being happy in life and being shackled by nobody's chains. You are your own man!!
Keep happy, of course, is good because everyone should smile.
Keep busy is grammatically correct, which gets extra points.

Keep warm is like, bad, because I dislike warm weather.
Keep loud is not a positive message because you might damage your ears and/or disturb people around you!
Keep healthy - hm. I forgot why I put this here. Uh... um, something something exercise is bad?
Keep full is implying a negative message of constant, no-holds-barred consumerism.
Keep empty... nobody should be empty inside, and for that matter, nobody should be empty inside al of the time.
Keep sad - see above!