acknowledge vs question

acknowledge

verb
  • To admit the knowledge of; to recognize as a fact or truth; to declare one's belief in 

  • To own as genuine or valid; to assent to (a legal instrument) to give it validity; to avow or admit in legal form. 

  • To own or recognize in a particular quality, character or relationship; to admit the claims or authority of; to give recognition to. 

  • To be grateful of (e.g. a benefit or a favour) 

  • To report (the receipt of a message to its sender). 

question

verb
  • To ask questions of; to interrogate; to ask for information. 

  • To ask a question or questions; inquire or seek to know; examine. 

  • To raise doubts about; have doubts about. 

noun
  • A subject or topic for consideration or investigation. 

  • A sentence, phrase or word which asks for information, reply or response; an interrogative. 

  • A proposal to a meeting as a topic for deliberation. 

  • A doubt or challenge about the truth, accuracy, or validity of a matter. 

How often have the words acknowledge and question occurred in a corpus of books? (source: Google Ngram Viewer )