どうして彼女はそんなに怒ったのか。

why?; for what reason; how; in what way; for what purpose; what for

she; her; her; girlfriend; sweetheart

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

so much; so; like that

to get angry; to get mad; to tell someone off; to scold; to be angular; to be square

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way