1+2) The verb pattern is "(es) wird jemandem (Dat) X". You know you need the dative case, because it's an instance of this pattern. It's not passive, because "werden" is used as a full verb, not as an auxiliary verb, which you know because there's no participle. 3) "wer weiß was um X geben" is a specifix expression, Lisa has already translated it.

1. it's not nominative case, it's dative. 3rd person dative is "ihr". If you'd use the nominative case it would be "Doch jetzt wurde -sie- wieder kalt." ; which is technically right and has the same meaning, but just doesn't sound as natural for the sentence as "ihr". 2. "Evis head was throbbing (rumbling?), her mouth was getting dry." 3. "I'd give whatever it takes, if I could."

Atun, about sentence 1, please remark the "really German" expressions below: * Mir ist kalt. - I feel cold. * Mir ist schlecht. - I feel queasy. * Dir wird kalt - you will (slowly) feel cold. There is no nominative case to be found in these sentences. The nominative would be an "es", which is ommitted. You could also say * es ist mir kalt, es ist mir schlecht, es wird Dir kalt. In modern German, however, this sounds bulky. For sentence 3: "wer weiss was" means "a lot" or "whatever it takes". "Viel darum geben" means "do a lot for something" Here, you have two "very German" expressions in one sentence. I think even very very advanced learners would struggle with this one.