当泡泡膜愈来愈薄时，颜色会变蓝，再由紫红色转成黄色。

As they get thinner, they will turn blue, then a purple-red color, then yellow.

youdao

当泡泡膜愈来愈薄时，颜色会变蓝，再由紫红色转成黄色。

As they get thinner, they will turn blue, then a purple-red color, then yellow.

youdao