So far the sentence is doing its job perfectly nicely. But you knew I wouldn’t stop there, because my student didn’t stop there.
“A day-care center is the best possible decision for any working mother, especially one that is clean and regulated by the state, with rules and goals.”
Suddenly the sentence turns into a nightmare for those who fear the encroachment of government into family life, and also for those who fear the heavy hand of those politicians who don’t believe women can think or act responsibly on their own.
To be “clean,” would a mother have to be drug-free (including Valium or Xanax), or would a recent shower be enough? Would she have to be clean in thought, word, and deed, like a Girl Scout? (Evidently Girl Scouts stopped having to promise this in 1970, but maybe it still would apply to working mothers.) And the regulation is only in terms of “especially,” which implies that occasionally a dirty (on drugs? unbathed? hot-to-trot cussin’ mama?) mother might be permitted to choose a day-care center too. Would the other children shun her kid, though?
Would the state’s regulations stop at cleanliness standards (how tested, by the way?), or would there be other standards of behavior? Would she, for example, be expected to be church-going? have a good credit rating? keep the house clean? serve up balanced meals? dress modestly? have a high school diploma?
My student wants additional “rules and goals,” too. Maybe all the Girl Scout Laws would be implemented. Maybe said mother would have to demonstrate some intention to get a promotion at work, or get a college degree, or become President. Would she have to have goals for her children, or only for herself?
Come to think of it, how would such a busy-body state feel about her working at all?
Oh! I see what my student meant—a day-care center that is clean etc. Well, why didn’t he say so? That pronoun “one” really did seem to be modifying “mother,” and therefore all the adjectives modifying “one” seemed to be describing that mother. Wow! I should have known what he meant!
Of course I did. That’s why I wrote the sentence down.
But that’s the experience of any reader who encounters this sentence: first the misunderstanding occasioned by the grammar; then the forehead-slap; then the articulation of the intended meaning. And then the necessary recursion to the sentence that precedes the one in question in an attempt to pick up the author’s thread of reasoning after having lost it in that spectacular way. If the reader has paused to laugh at some point in this process, and even (like me) to formulate an understanding of the point on the basis of the misunderstanding of the sentence, then the thread is even harder to find, let alone pick up. At that point, unless the reader is an instructor of writing and the writer is a student, the reader may just give up, set the whole thing aside, and move on to some more lucid essay.
And that’s why grammar matters.