几乎不言自喻,科学教师在引进一个新的术语时,应该给它作出定义。但是,这个通常值得称赞的惯例在某些时候也许以回避为宜。 1971年3月,我查阅了十二种中学物理学教科书上的能量的定义。有八本书,或在术语表,或在正文,都有简括的定义。其中五本书 It is almost self-evident that when science teachers introduce a new term, they should define it. However, this usually commendable formula may be appropriate at some point. In March 1971, I checked the definition of energy in twelve textbooks for middle school physics. There are eight books, either in the glossary or in the text, with a brief definition. Five of them