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.
embark on   proportional to   under way   response to   deficient in   come into one's own   contend with   in memory of   be packed with   no wonder   allow for   be associated with
We mut_________the possibility that he is not here because of illness.
【正确答案】：allow for