particle lens

例句：

1. 1. The particles in the air are so small that they can't be seen with the naked eye.
   空气中的粒子如此之小，以至于肉眼无法看见。
2. 2. The scientist found that the particles of the substance were different from those of the other sample.
   科学家发现这种物质的粒子与另一种样本的粒子不同。
3. 3. The particles in the paint were too small to see clearly.
   油漆中的粒子太小，看不清楚。