citeren  to quote

coderen  to encode

combineren  to combine

communiceren  to communicate

concentreren  to concentrate

concluderen  to conclude

condoleren  to offer condolences

confronteren  to confront

constateren  to establish/observe

consulteren  (to consult)

contracteren  (to contract/hire)

controleren  (to check/inspect)

corrigeren  (to correct)