A friend sensitive to the care needed for newborns and their moms was touched by a sign promising "Infant Hearing Testing." The sight of the sequential hearing and testing got her thinking about the five senses: sight, of course, plus touch; then there's smell, taste, and hearing.

Why, she wondered, are four of the five senses brief, one-syllable nouns, while one of them—hearing—is a more cumbersome gerund (or verbal noun)? We're pleased to be able to say her query did not fall on deaf ears. (来源：英语e问e答 http://ask.englishcn.com)

As to why four out of five external senses have noun senses that physically resemble their verb senses, we can't offer any more explanation than this: English is quirky. But we can point out that those five senses do have other labels, too: sight is also known as vision; taste as gustation; smell as olfaction; touch as taction; and hearing as audition. (来源：EnglishCN英语博客基地)

Neither taction nor audition seem especially common, and we are happy to speculate about why that might be. Touch is well-established, and may be more easily understood than taction. And of course audition has multiple meanings, so that Infant Audition Testing might prove confusing. (来源：英语交友 http://friends.englishcn.com)