interesting前面加an。
interesting是以元音因素开头，所以前面应加不定冠词an。例如：He told us an interesting story just now. 刚才他给我们讲了个有趣的故事。
有些英语单词虽然以辅音字母结开头，但是却以元音因素开头，所以前面应该用不定冠词an。例如：an hour(一小时)，an honest man(一个诚实的人)， an honor(一份荣誉)等。
前面加an，例如：
1.That looks like an interesting book.那好像是本有趣的书。
2.There was an interesting sequel to these events later in the year.这几件事发生以后，当年就出现了一种有趣的结果。
3.She gave an interesting talk on her visit to China.她做了个关于她在中国访问的有趣报告。
