1. 这是个什么词？
词：occasional
英英释义：happening sometimes but not often or regularly
例句：Although I am well traveled, I have mostly visited different parts of my own country and have made only occasional overseas trips.
2. 为什么选这个词？
名词“occasion”有很多个意思，比如“场合” “时机” “特别时刻”等。它的形容词“occasional”意思比较单一，是“偶尔的”，常用、好用，值得掌握。它的副词“occasionally”（“偶尔地”）也可以顺便收入囊中。当我们想表达某个现象偶然才出现或某个事件偶然才发生时，除了使用 sometimes, from time to time, every now and then 之外，还可以使用 “occasional”和“occasionally”，尤其是在书面表达中。
我们来看几个例子。 华裔美国德州扑克高手 Johnny Chan 胜率极高，偶尔才会输给对手，就可以说：
Johnny Chan is a formidable poker player and only loses very occasionally.
再比如，我去过不少地方，但很多都是国内的各个省份，时不时才去国外旅行一次，就可以说：
Although I am well traveled, I have mostly visited different parts of my own country. I have traveled abroad only occasionally.
或
Although I am well traveled, I have mostly visited different parts of my own country and have made only occasional overseas trips.
《经济学人》在一篇写纽约的 Christmas special 文章中有这么一句：
An occasional plane passes overhead, perhaps to La Guardia, perhaps to JFK.（La Guardia 和 JFK 是纽约市的两大机场。）
《经济学人》有一篇讣告写的是一个暴徒，里面有这么一句：
He occasionally regretted the shame he had brought on his family, but for his victims and their relatives he felt nothing.
3. 怎样学会使用这个词？
1）翻译下面的句子：
露西擅长山水画，偶尔也画画油画。
Lucy is good at landscape painting, and she paint accasional oil-painting.
（参考翻译：Lucy is especially good at traditional Chinese landscape painting, but occasionally she does oils too. 或 Though an expert on traditional Chinese landscape painting, Lucy does occasional oil painting too. ）
2）结合自己的生活、学习、工作、兴趣等，想象在什么语境下会用到这个表达。先简要描述这个场景，再造句。
场景:我大部分时候心情舒畅，偶尔心情不好。
造句:I feel comfortable mostly, with accasional bad feeling.