Complex sentence: The geographic range of the marsh shrew extends from southwest British Columbia, along the western regions of the U.S. states of Washington and Oregon and through northwestern California to the area north of San Francisco.
Split into simpler sentences: The geographic range of the marsh shrew extends from southwest British Columbia along the western regions of the US states of Washington and Oregon. The range extends through California along the western aspects of the northern part of the state to the area north of San Francisco.