v. expel (gases or odors)
v. give off, send forth, or discharge; as of light, heat, or radiation, vapor, etc.
vt. 发出, 放射, 发表(意见等), 散发, 发行
[化] 放射
1. The factory will emit smoke if the machines are not properly maintained.
如果机器没有得到妥善维护，工厂会排放烟雾。
2. Trees emit oxygen, which is essential for our survival.
树木释放氧气，这是我们生存所必需的。
3. The light bulb will emit a bright light when turned on.
灯泡打开时会发出明亮的光。