In Osborn v. Mission Ready Mix (1990) 224 Cal.App.3d 104, the plaintiff was injured after falling over some concrete pieces on the defendant's property. (Id. at p. 110.) The Osborn court concluded the trial court had properly admitted the plaintiff's testimony regarding "whether the nature of the potential danger was obvious or not," because this "was a matter which could best be described to the jury by way of opinion testimony." (Id. at p. 113.) The Osborn court reasoned: "A recitation of the size of the area, the depth and quality of the dirt, the size of the concrete pieces and whether and in what proportion they were totally exposed, completely hidden, or partially embedded in the dirt could be made, but, in our opinion, such facts alone would not make the obviousness of the risk involved so palpable to the jury that its means of forming an opinion would be practically equal to those of the witness." (Ibid.) The Osborn court did conclude the plaintiff's testimony as to the "as to the 'reasonableness' of the condition of defendant's premises was not helpful to a clear understanding of his testimony, and invaded the province of the jury" (id. at p. 114), reasoning this testimony called for a legal conclusion as to the ultimate issue in the case, namely, whether the property had been kept in a " 'reasonably safe condition.' " (Id. at p. 113.)