微风拂过湖面，激起层层细小的波纹。

The gentle wind made small ___wavelets ripple across the lake.

他的笑话在教室里激起了一阵阵欢笑的涟漪。

His joke sent ___wavelets of laughter rippling through the classroom.

工程师使用小波来分析地震信号中的局部特征。

Engineers use ___wavelets to analyze localized features in seismic signals.