Reflection of a beam of light on the diaphragm falls on a phototransistor.经膜片反射的光束照射到光敏管上.A beam of light produced by a laser can weld metals.激光器发生的光束可以焊接金属.A beam of light produced a laser can weld metals.激光器发生的光束可以焊接金属...

一束光...

a beam of light的音标：a beam of light的英式发音音标为：[ə bi:m ɔv lait]a beam of light的美式发音音标为：[e bim ʌv laɪt]...