Assertion: dog's time | /r/HasProperty | difficult
Facets:
value: to date
type: TEMPORAL
Source sentences:
text: (Note: this means that dogs with docked tails have a difficult time using this mode of communication.
text: Secondly, the genetic divergence between the dog and modern wolves occurred over a short period of time, so that the time of the divergence is difficult to date (referred to as incomplete lineage sorting).