どんな
what kind of, what sort of
どうして
why, for what reason, how
どうやって
how, in what way, by what means
が
subject marker/ identifier particle
が
but, however
がある
there is, is (non living things)
がいる
there is; to be; is (living things)
(が) 欲しい = ほしい
to want something
方がいい = ほうがいい
had better; it would be better to; should
暖かい = あたたかい -> 暖かく
i-adjective to adverb
美味しい = おいしい -> おいしく(ない)
i-adjective when conjugated