In the Business Directory, people can write a review or leave a star rating by logging in (or create an account if they do not have one), then login to either leave a review and select a rating... or they can just click a star to leave a rating without leaving a review.
Not all listings have reviews. When someone has only selected a star rating there will not be a review to read, just the star rating.
If someone has left a review for a listing you will see an option to read the review(s). You can read the review by clicking the "Reviews" link in the menu located on the right-side of the listing (see example below).
Note: If the "Reviews" link is not visible it means there are no reviews for that listing.