1. 下来;下降;走下
    If you descend or if you descend a staircase, you move downwards from a higher to a lower level.

    e.g. Things are cooler and more damp as we descend to the cellar...
           当我们往下走去地窖时，四周愈见阴冷潮湿。
    e.g. She descended one flight of stairs.
           她走下了一段楼梯。

2. (情绪、气氛等)降临，笼罩
    When a mood or atmosphere descends on a place or on the people there, it affects them by spreading among them.

    e.g. An uneasy calm descended on the area...
           一种令人不安的平静笼罩了该地区。
    e.g. A reverent hush descended on the multitude.
           人群虔敬地噤了声。

3. （大批人）突然到来，突然造访
    If a large group of people arrive to see you, especially if their visit is unexpected or causes you a lot of work, you can say that they have descended on you.

    e.g. 3,000 city officials descended on Capitol Hill to lobby for more money...
           3,000名市政官员齐聚国会山，为筹集更多的款项进行游说。
    e.g. Curious tourists and reporters from around the globe are descending upon the peaceful villages.
           好奇的游客和记者从世界各地一齐涌向这些平静的村落。

4. (夜幕、黄昏、黑暗等)降临
    When night, dusk, or darkness descends, it starts to get dark.

    e.g. Darkness has now descended and the moon and stars shine hazily in the clear sky.
           夜幕现在已经降临，晴朗的天空里月影婆娑，星光朦胧。

5. 降低身份;堕落;沦落
    If you say that someone descends to behaviour which you consider unacceptable, you are expressing your disapproval of the fact that they do it.

    e.g. We're not going to descend to such methods...
           我们不会沦落到使用这种手段。
    e.g. She's got too much dignity to descend to writing anonymous letters.
           她是个自尊心很强的人，绝不会自贬身份去写匿名信。

6. 陷入(糟糕境地)
    When you want to emphasize that the situation that someone is entering is very bad, you can say that they are descending into that situation.

    e.g. He was ultimately overthrown and the country descended into chaos.
           他最终被推翻，整个国家则陷入了混乱。