An overlay showing population can be placed on top of the map.
可以在地图上加一层显示人口的透明膜。
《牛津词典》
2
During commercials, an overlay will appear at the bottom of the screen, prompting viewers to press a button to request a free sample or order a catalogue.
在商业广告播放时，一个弹窗将会出现在屏幕下方，促使观众按动按钮，以索要免费样品或订阅产品目录。
3
During commercials, an overlay will appear at the bottom of the screen, prompting viewers to press a button to request a free sample or order a coupon or a catalogue.