Abbreviations have been written using a period to mark the part that was deleted. In the case of most acronyms, each letter is its own abbreviation, and in theory should have its own period. This usage is however becoming outdated as the use of capital letters is sufficient to indicate that the word is abbreviated. Nevertheless some popular style guides still insist on the muliple periods style with unpronounceable abbreviations, such as USA, but not with pronounceable ones such as RAM.
这句中的period的是什么意思，还有最后一句化是什么意思？怎么翻译？谢谢！
參考答案:period: 音节
然而一些流行文体指南坚持用不可（直）读的音节缩写，如USA，而不用那些可（直）读的音节缩写，如RAM。
