1. (使)变强烈(或紧张);(使)加剧
    If a situation or emotion deepens or if something deepens it, it becomes stronger and more intense.

deepen的意思

    e.g. If this is not stopped, the financial crisis will deepen...
           如果不对其加以阻止，财政危机将会加剧。
    e.g. If anything, Sloan's uneasiness deepened...
           如果说有什么不一样的话，那就是斯隆变得越来越不安了。

2. 加深，深化，增进（知识或理解）
    If you deepen your knowledge or understanding of a subject, you learn more about it and become more interested in it.

deepen的意思

    e.g. He did not get a chance to deepen his knowledge of Poland.
           他没有机会更深入地了解波兰。

3. （使）(光线或颜色)变暗;（使）变深
    When light or a colour deepens or is deepened, it becomes darker.

    e.g. Dusk was deepening as they drove back to the lights of Shillingham...
           他们驱车返回华灯初上的希灵汉姆时，暮色渐浓。
    e.g. This spice is used particularly in poultry feed to deepen the colour of egg yolks.
           这种香料尤用于家禽的饲料中，以加深蛋黄的颜色。

4. （使）(声音)变低沉
    When a sound deepens or is deepened, it becomes lower in tone.

    e.g. Her voice has deepened and coarsened with the years...
           她的声音随着岁月流逝变得低沉而沙哑。
    e.g. The music room had been made to reflect and deepen sounds.
           这间音乐室经过特殊设计处理，能够反射声音，使声音变得低沉厚重。

5. (呼吸)变深长;加深(呼吸)
    When your breathing deepens, or you deepen it, you take more air into your lungs when you breathe.

deepen的意思

    e.g. He heard her breathing deepen...
           他听到她的呼吸变深了。
    e.g. When you are ready to finish the exercise, gradually deepen your breathing.
           准备结束练习时，要慢慢地深呼吸。

6. 挖深
    If people deepen something, they increase its depth by digging out its lower surface.

    e.g. ...a major project to deepen the channel...
           挖深水道的重大工程
    e.g. The tunnels have been widened and deepened.
           各条隧道都已拓宽加深。

7. (河流、海洋等)变深
    Something such as a river or a sea deepens where the bottom begins to slope downwards.

    e.g. As we drew nearer to it the water gradually deepened.
           我们靠近它时，水渐渐深了起来。