Sentence:  Talking of the rapid population growth ( upwards of 12000 babies born daily ) with an immigrant entering the United States every 1 - 1 2 minutes , he said `` our organization has not been <WSD>keeping</WSD> pace with this challenge '' . 
Meaning of the word marked with <WSD> tags:  keep in a certain state, position, or activity; e.g., "keep clean"