I think it’s high time we talked about the dative case, which requires a little exploration of direct and indirect objects. To further this purpose I’ve constructed a little example for you. We’ll try this sentence two ways:
Sue gave Bob her phone number.As you can see, whether you’re assuming “to” Bob in the first example or congratulating him after the second, the man indirectly receives the action of the verb no matter how direct Sue may have been with him. The phone number gets the giving here and Bob is the indirect object thereof. You can’t use such a verb without an indirect object, but the direct object will always be what is being given or shown.
Sue gave her phone number to Bob.
Now I hear you asking, “What if I wrote ‘Sue gave at the office’?” In this case, your reader assumes the direct object to exist. While our giving friend Sue could have donated anything from half a bologna sandwich to a thousand dollars the crux of the matter remains that she gave something. One also guesses that she handed it to someone or sent it to some place, but that indirect object also declines to appear in this idiom (the general intent of which is to remain non-specific). “At the office” is just a prepositional phrase, not an object of any sort.
Shockingly, I haven’t yet made my point, which was that indirect objects (and any adjectives describing them) take the dative case. And what, pray tell, does that mean to your day-to-day writing life? In most cases it affects your writing very little as the case does not require specialized word forms. You should care simply because, someday, someone might as you to explain the dative case. Alternatively you could take up translating Latin (or a less-dead language) and need to know what to do with those dative forms when you find them.