ray focusing

例句：

1. 1. The camera isdesigned to focus on the subject in theforeground.
   这台相机设计用来聚焦前景的主体。
2. 2. The scientist focused his attention onthe problem at hand.
   科学家把注意力集中在手头的问题上。
3. 3. The artist concentrated on creatinga masterpiece with each stroke of thebrush.
   艺术家专注于用每一笔创作杰作。