1. 过滤
    To filter a substance means to pass it through a device which is designed to remove certain particles contained in it.

    e.g. The best prevention for cholera is to boil or filter water, and eat only well-cooked food.
           预防霍乱的最佳方法是将水煮沸或过滤，并且只食用煮熟后的食物。

2. 滤器;过滤器
    A filter is a device through which a substance is passed when it is being filtered.

    e.g. ...a paper coffee filter.
           咖啡过滤纸

3. 滤声器;滤光器;滤波器
    A filter is a device through which sound or light is passed and which blocks or reduces particular sound or light frequencies.

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    e.g. You might use a yellow filter to improve the clarity of a hazy horizon.
           可以使用黄色滤光器让模糊的视野更加清晰。

4. (光或声)隐约透过，缓缓传至
    If light or sound filters into a place, it comes in weakly or slowly, either through a partly covered opening, or from a long distance away.

    e.g. Light filtered into my kitchen through the soft, green shade of the cherry tree.
           光线透过樱桃树柔和的绿阴隐约照进我的厨房。

5. (消息等)走漏，慢慢传开
    When news or information filters through to people, it gradually reaches them.

    e.g. It took months before the findings began to filter through to the politicians...
           调查结果数月后才传到从政者的耳朵里。
    e.g. News of the attack quickly filtered through the college.
           有关袭击的消息很快就在该学院中传开了。

6. (路口的)转弯信号灯(或车道)
    A traffic filter is a traffic signal or lane which controls the movement of traffic wanting to turn left or right.

7. 滤除;滤掉
    To filter out something from a substance or from light means to remove it by passing the substance or light through something acting as a filter.

    e.g. Children should have glasses which filter out UV rays...
           儿童应该戴上滤除紫外线的眼镜。
    e.g. Plants and trees filter carbon dioxide out of the air and produce oxygen.
           花草树木会过滤掉空气中的二氧化碳并制造氧气。

相关词组：filter out