学习目标
掌握本节生词及句型表达与运用。
词汇运用
重点词汇讲解：
1. occasion n．重要的社交活动；时刻；时候
(1)on one occasion 有一次
on that occasion 那时；在那种情况下
on occasion 偶尔
(2)occasional adj. 偶尔的；不经常的；特殊场合的
occasionally adv. 偶然地；偶尔；有时
①On one occasion, she called me in the middle of the night.
有一次，她半夜给我打电话。
②He has been known on occasion to lose his temper.
大家都知道他有时会发脾气。
③He managed to remain cool by swimming occasionally(occasion)．
他不时地游泳来使自己保持凉快。
