1. With scarcely a glance at the items, the clerk sweeps them across an aperture, where a special marking on each item is scanned by a low-powered laser beam inside the machine, connected to a remote computer.
    收款员几乎不看商品，只是把商品从机器上的孔眼处一扫而过，机器里的低能量激光对商品上的一个特殊标志进行扫描，这台扫描机与另一台电脑相联。

2. The beam from a flashlight showed a beggar sleeping at his doorstep.
    借用手电筒的光, 他看到了一个睡在他家门口的乞丐。

3. The beam has begun to sag.
    横梁开始下垂了。

4. The scanning laser beam was an ideal device for reading these markings, and so the Universal Product Code was born.
    能进行扫描的激光是一阅读这些标志的理想手段，因而通用条形码便应运而生了。

5. Hold the flashlight so that the beam shines straight down on a sheet of white paper.
    手握电筒让光线直射在一张白纸上。

6. As the grocery items moves along the conveyor belt, the checker passes each item over a glass plate in the counter top, making sure that the UPC symbols can be read by the laser beam under the glass.
    食品杂货经传送带传到收款员跟前，收款员随即将每一物品搁在柜台上的一块玻璃板上一扫，好使板下的扫描机阅读条形码。