重点讲解：
1. of all
（用于强调first， last或最高级形容词或副词）最，最为；
eg. Now she faces her toughest task of all.
现在她面临着最艰巨的任务。
eg. They are the most dependable of all.
他们是最为可靠的。
2. ascribe...to
把…归因于；把…归咎于；
eg. An autopsy eventually ascribed the baby's death to sudden infant death syndrome.
尸检最终认定孩子死于婴儿猝死综合征。
eg. He ascribes his success to good luck.
他把他的成功归功于幸运。
3. owe...to
应把…归因（于）；应把…归功（于）；
eg. I always suspected she owed her first job to her friendship with Roger.
我一直怀疑她仗着自己是罗杰的朋友才得到第一份工作。
eg. He owed his survival to his strength as a swimmer.
他是因为水性好才幸免于难的。
4. at work
起作用；发挥效用；
eg. The report suggested that the same trend was at work in politics.
这份报告表明，同一趋势也在影响着政治。
eg. It is important to understand the powerful economic and social forces at work behind our own actions.
重要的是，要理解在我们自身行动背后起作用的强大的经济和社会力量。
5. because of
因为；由于；
eg. Many families break up because of a lack of money.
许多家庭由于缺钱而破裂。
eg. Many beautiful fish are fast disappearing because of the severe pollution.
因为污染严重，许多美丽的鱼类正在面临绝种。