1、descent

下降;降落

Sixteen of the youngsters set off for help, but during the descent three collapsed in the cold and rain.

16 名年轻人出发去寻求帮助，但在下山过程中有 3 人因寒冷和大雨晕倒了。

the crash of an Airbus A300 on its descent into Kathmandu airport.

空客 A300 在加德满都机场降落时的坠毁

(形势的)恶化;(人的)堕落，沦落

The only lasting solution lies in a political settlement. Without it, their descent into chaos will be guaranteed.

唯一的长久之计是通过政治手段解决。否则，他们势必会陷入一片混乱。

his swift descent from respected academic to struggling small businessman.

他从一名受人尊敬的学者到一个度日艰难的小商人的瞬间沦落

血统;家世;出身

All the contributors were of African descent.

所有的撰稿人都是非裔人士。

2、operation

（由大量人员参与、具有高度组织性的）活动，行动，工作

The rescue operation began on Friday afternoon.

救援行动于星期五下午开始。

The soldiers were engaged in a military operation close to the Ugandan border.

这些士兵参加了乌干达边境附近的一次军事行动。

使用；运作

Until the rail links are in operation, passengers can only travel through the tunnel by coach.

在铁路连线开通之前，乘客只能乘坐长途客车穿越隧道。

the free banking system that has been in operation since the early eighties.

从80年代初就开始实行的自由银行制度

（使）施行；（使）实行；（使）生效

The Financial Services Act came into operation four years ago.

《金融服务法》于4年前开始实施。

Cheaper energy conservation techniques have been put into operation in the developed world.

更经济的节能技术在发达国家已经投入使用。