1. 释义：happening sometimes but not often or regularly

2. 理解：名词occasion有很多意思，比如“场合、时机、特别时刻”等。它的形容词occasional意思比较统一，是“偶尔的”，常用、好用，值得掌握，它的副词"occasionally"(“偶尔地”）也可顺便掌握。当我们想表达某个现象偶尔才出现，某个事件偶尔才发生，除了用sometimes, from time to time, every now and then之外，还可以用"occasional""occasionally",尤其书面表达上。

3. 应用：

1）翻译：露西擅长山水画，偶尔也画画油画。

Lucy is good at Chinese traditional landscape painting, but occasionally she does oil paintings too.(或者Lucy is good at Chinese traditional landscape painting, but she does occasional oil paintings too.)

2) 造句：

The boys in our class like playing football, but occasionally they play basketball as well.

The boys in our class like playing football, but they play occasional basketball too.

（我们班的男生爱踢足球，偶尔也打篮球。）