So I'm going through the sentence correction on the official guide and through the first 50 and have only missed 4.... however, i think these are pretty easy...i've looked ahead a little bit and they dont seem to get much harder....does anyone know of a good place to find a bunch of really tough SC questions with explanations? How about a comprehensive list of frequently appearing idioms(found a couple of lists but I'm still finding ones in questions not on the list)...thanks in advance for any tips