<span>She promised to come back someday.</span>
Answer:
the sentence is an object of a preposition. is that what you're trying to know?
Knows little. 2 and 3 are both presuming too much, as it's the writer's duty to get them interested and informed. 4 basically doesn't matter, and furthermore may not even apply in many forms of writing. 1 is the best answer, as writing for general audiences is intended to inform and expand the horizons of the reader.
