occasional
adj. 偶尔的, 不经常的;临时的
1.This thing isn't occasional.
这件事不是偶然的。
2.They talked until dawn,and have stayed in occasional touch.
现在，他们还偶尔保持联系。
3.We must figure in occasional expenses in the budget.
我们必须在预算中把临时费用估计在内。
occurrence
n. 发生, 出现；事件; 发生的事
辨析：occurrence，happening都可指意外或计划中发生的“事件、事情”，occurrence也可指日常或普通家庭中的事情。
1.The occurrence of storms delayed our trip.
暴风雨延误了我们的旅行。
2.Newspapers record the chief occurrences of the day.
报纸报道了当天发生的大事。
3.Vandalism used to be a rare occurrence.
故意破坏公共财产的行为过去极少发生。
outset
n. 开始, 开端；初级阶段
搭配： at the outset 开始时
from the outset 从一开始
1.I warned you at the outset not to trust him, and you wouldn't listen to me.
一开始我就警告过你不要信任他, 可你不肯听我的话。
2.From the outset it was clear that be was guilty.
一开始就已清楚，他是有罪的。
3.Everything went rather smooth at the outset of her career.
再她事业的初期，一切都相当顺利。
overcome
vt. & vi. 战胜; 克服
vt. 被（感情等）压倒, 使受不了
搭配：overcome difficulties 战胜困难
overcome one's shortcomings 克服缺点
be overcome withliquor 喝醉
1.They overcame the enemy easily.
他们轻松地战胜了敌人。
2.He has enough courage to overcome the difficulty.
他有足够的勇气来克服这个困难。
3.They were overcome with sadness.
他们悲痛欲绝。
