If I write “XXX is as difficult as preposition” today, is it a normal sentence and can be understood here in Taiwan or abroad?

If I write “XXX is as difficult as preposition” today, is it a normal sentence and can be understood here in Taiwan or abroad?
Years ago, I read a sentence from China Post, which very possibly was written by the well-known English expert of former Japanese and English councilor(interpreter) for “李登輝” or American Professor at 輔仁大學, which said “ XXX is as difficult as preposition”.
At that time, I just thought that “the preposition is decided by the word (words, phrase) before or after the preposition – the verb before it or the noun after it. But today, I know from Yahoo – International that a preposition sometimes is decided by the whole sentence.
Because I can’t find “as difficult as preposition” on the internet. So I’m doubting if write this sentence today without too much context, can it be acceptable here in Taiwan or abroad?
Thanks for any opinions.