78：在以下的句子里,a和an是否可以互相替换使用？ 哪个是比较合适的冠词？

QUESTION 78: Is it correct to use "a" and "an" interchangeably in the following sentence?    That is a/an historic part of town.    If not, which would be the correct determiner?
    
ANSWER: The "h" in "historic" is known as an "h" aspirate and this is usually preceded by "an". e.g. AN historic; AN hotel

However, it is more and more common to hear people saying "a hotel" and "a historic novel" and it seems that this is an example of usage in transition -- it could be that the use of "an" with aspirates will disappear from English in the future.    For now, the grammatically accepted answer can be "a" or "an" ... But on the street you can take your pick!

问题78：在以下的句子里,a和an是否可以互相替换使用？ That is a / an historic part of town. 如果不能，哪个是比较合适的冠词？

回答：historic这个词里的"h"被认为是送气的"h",所以通常前面加"an"。
如：AN historic... / AN hotel。

但是，越来越多的人说"a hotel", "a historic novel"，这似乎是用法的变化，在将来，可能送气的"h"要加"an"的用法会在英语里消失。现在，语法上承认的答案是用 a/an，不过，在生活中，你可以任意选择。