background projector

例句：

1. 1. The backgroundprojector was used to illuminate the room during the presentation.
   在演示期间，背景投影仪被用来照亮房间。
2. 2.The new background projector has a higher resolution than the old one.
   这款新的背投式投影机比旧的分辨率更高。
3. 3.The background projector was set up in a corner of the classroom for better viewing angles.
   教室的一个角落被设置成背景投影仪的位置，以便更好的观看角度。