英汉词典

1. 发出，排放，散发（热、光、气或气味）
    If something emits heat, light, gas, or a smell, it produces it and sends it out by means of a physical or chemical process.

    e.g. The new device emits a powerful circular column of light.
           新设备发出明亮的圆形光柱。
    e.g. ...the amount of carbon dioxide emitted.
           二氧化碳排放量

2. 发出（声音或噪音）
    To emit a sound or noise means to produce it.

    e.g. Polly blinked and emitted a long, low whistle.
           波莉眨了眨眼，吹了一声低沉而悠长的口哨。