1. 管子;管;管状物
    A tube is a long hollow object that is usually round, like a pipe.

    e.g. He is fed by a tube that enters his nose.
           他靠鼻饲管进食。
    e.g. ...a cardboard tube.
           纸卷芯

2. (内盛膏状物等的)管状容器
    A tube of something such as paste is a long, thin container which you squeeze in order to force the paste out.

tube

    e.g. ...a tube of toothpaste.
           一管牙膏
    e.g. ...a small tube of moisturizer.
           一小管保湿液

3. 管状器官;管;道
    Some long, thin, hollow parts in your body are referred to as tubes .

    e.g. The lungs are in fact constructed of thousands of tiny tubes.
           肺实际上由上千条细微的气管构成。

4. (伦敦的)地铁
    The tube is the underground railway system in London.

    e.g. I took the tube then the train and came straight here...
           我先乘地铁，然后坐火车直奔这里。
    e.g. He travelled by tube.
           他乘地铁旅行。

5. 电视机
    You can refer to the television as the tube .

    e.g. The only baseball he saw was on the tube.
           他看过的唯一一场棒球赛是在电视上看的。

6. （公司、经济、机构）完全垮掉，彻底崩溃，告吹
    a business, economy, or institution goes down the tubes or goes down the tube, it fails or collapses completely.

    e.g. The country was going down the tubes economically...
           该国经济正在彻底崩溃。
    e.g. When I was dieting, that was when my social life started going down the tube.
           我节食的时候，也就切断了一切社交生活。

7. see also: bronchial tube;cathode-ray tube;fallopian tube;inner tube;test tube