tion expresses actual performance in a particular
            action; for example, <a
            href="./doing-vocab.html#performanceLevel">(#$performanceLevel</a>
            Joe DiggingHole54001 <a
            href="./actor-vocab.html#performedBy">#$performedBy</a>
            #$Strength #$Low) means Joe exerted a low level of strength
            while digging that particular hole. This does not imply much
            about Joe's potential to exert strength, about strength
            required in genera