well-defined beam

例句：

1. 1. The engineer designed a well-defined beam to support the structure.
   工程师设计了一个明确的光束来支撑结构。
2. 2. The scientist used a well-defined beam to measure the distance between two points.
   科学家使用一个明确的光束来测量两点之间的距离。
3. 3. The physicist explained that the well-defined beam was crucial for the experiment's success.
   物理学家解释说，明确的光束对于实验的成功至关重要。