Fill in the blanks, each using one of the given words or phrases

Fill in the blanks, each using one of the given words or phrases below in its proper form.
look into   next to   show up   line with deficient in   compatible with   take off   bring into play   run down   after all   be concerned with   be associated with
He said these books_________the application of the theory to practical business problems.
【正确答案】：were concerned with