occur to: 发生在
An irony that did not occur to her until much later.
直到很久以后她才想到那是一件讽刺的事。
The effects of the disease are usually bilateral although they may occur to different degrees.
疾病的影响通常具有两面性，尽管它们可能产生不同的影响程度。

play out: 逐渐发生; 展开; 结束
How this debate will play out in beijing remains unclear.
目前尚不清楚，中国政府将如何结束这场辩论。
No one can say how these two trends will play out.
没有人能说清楚这两种趋势最终将是如何演绎。

engage in: 参加，忙于
They tempt you to engage in non-restful activities and keep you awake.
它们诱惑你从事不能休息的活动让你保持清醒。
Microsoft corp. and yahoo inc. have disclosed that they engage in some form of behavioral targeting.
微软公司和雅虎公司也已经透露它们从事了某种形式的行为定向的技术研发。