strain这个单词意思极多。字典里面的意思也基本上都见过了，下面我来总结一下：

名词：1，表示压力，拉力，其意义可抽象，可具体。

              Their marriage is under great strain at the moment.(抽象）

              stresses and strains

              The ground here cannot take the strain of a large building.（具体）

          2，拉伤，如肌肉的拉伤 a leg strain腿部拉伤

          3，重压出现的问题或担忧 The transport service cannot cope with the strain of so many          additional passengers.

          4,动、植物的）系，品系，品种；（疾病的）类型

     a new strain of mosqiotoes resistant to the posion

    5,个性特点，禀性He had a definite strain of snobbery in him.

    6,乐曲，曲调，旋律He could hear the strains of Mozart through the window.

做动词时基本跟名词的时是一样的：

1，to strain  a muscle拉伤肌肉

2，I strained my ears(= listened very hard)to catch what they were saying.

 Necks were strained for a glimpse of the stranger.

3，strain every nerve to do sth.竭尽全力做某事

4，过滤Strain off any excess liquid. 滤掉多余的液体。

      to filter out dust particles/light/impurities 过滤掉尘粒；滤光；用过滤法除杂质

注意这里filter和strain在都作动词的时候是同义词，但是接的介词是不一样的

5，I wouldn't let my best guests strain her eyes.可不能让贵客眼睛疲劳。（这个是在老友记第六季第18集的Monica对Phoebe说的一句话)