Example 1: I gave my sister a cat for her birthday.
It's ambiguous, yes. Though my guess would be that it's an adverb of purpose; i.e., the reason I gave her a cat was because it was her birthday.
Example 2: I gave a cat to my sister.
'give' is ditransitive: "a cat" functions as the verb's direct object (DO). It's the thing being given. "to my sister" functions as the indirect object (IO). It's the recipient of the thing). Change the word order and its function remains the same:
EX: I gave my sister (IO) a cat (DO).
EX: I gave a cat (DO) to my sister (IO).
Example 3: The senator asked a question of the Supreme Court Justice.
Indirect object. It's synonymous with "to the Supreme Court Justice" Cf. She asked the Supreme Court Justice (IO) a question (DO).
What do "d" and "i" represent?The pattern SVOdOi doesn't exist, does it?
green + bombHow do you pronounce "Greenbaum"?