to experts: idiom help and more D:

<p>I know "Preoccupied with" is correct, but what about "preoccupied by"? i've seen that used frequently. </p>

<p>"preoccupation with" is also correct, but what about "preoccupation by"?</p>

<p>also, i know "occupied with/in/by" all work according to my dictionary; can someone clarify the differences in the three prepositions?</p>

<p>please distinguish what is grammatically correct and what is WRONG, not "generally not used" or w/e</p>

<p>thanks. oh and i've looked at several lists of idioms already, but do any of you have a compilation of really difficult idioms or a REALLY comprehensive idiom list......i find that many idiom lists are not really comprehensive or helpful in terms of difficulty...</p>

<p>and lastly, i've been wondering if any of you 2300+ takers have a list of really iffy grammar questions you've missed... i mean those 1 or 2 questions that trip up a perfect score</p>

<p>lol and uhm also as a disclaimer.....i've seen the many, many threads on idioms. i simply cant find a really definitive list of idioms... sometimes in the lists, all of the different prepositions for certain idioms are not stated, so they confuse me more than help me out. i'm looking for like some holy grail of idioms that has at least all the possible prepositions for the idioms listed. </p>

<p>ps: in an idiom list, if "preoccupied by" is not listed but "preoccupied with" is, does that necessarily mean that the former doesn't work? i.e., are these lists absolutely definitive and exclusive?</p>

<p>thanks!</p>

<p>For idiom errors, just remember the most commonly used one. Consider all others WRONG. It doesn’t matter what is grammatically correct, the CB only tests the most commonly used. </p>

<p>btw, “by” is not correct. “with” is the correct preposition for both of your “preoccupy” forms.</p>