飞艇冠军选号公式图片简介：A large tank filled with clean water has been prepared below. When the lead drops into the water, it cools down. When you pick it up, you will see that each piece is round and smooth, like the glass balls of later generations.
A large tank filled with clean water has been prepared below. When the lead drops into the water, it cools down. When you pick it up, you will see that each piece is round and smooth, like the glass balls of later generations.
