turn to vs undertake

turn to

verb
  • To start to do or to use something in an attempt to deal with a difficult and unpleasant situation. 

  • To consult for advice or help. 

  • Used other than figuratively or idiomatically: see turn, to. 

  • To become, to degenerate into. 

  • To direct one's attention or efforts toward something. 

undertake

verb
  • To take upon oneself; to start, to embark on (a specific task etc.). 

  • To commit oneself (to an obligation, activity etc.). 

  • To pass a slower moving vehicle on the curbside rather than on the side closest to oncoming traffic. 

noun
  • The passing of slower traffic on the curbside rather than on the side closest to oncoming traffic. 

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