The bacteria produce crystals that form around each grain of sand, locking together all the loose particles to form a solid brick.

细菌产生晶体包裹住每一粒沙，将这些碎颗粒紧紧锁住，形成一块结实的砖。

One day as Pat and Mike were walking down the sidewalk together, Pat put his hand on a solid brick wall and said, " Mike, hit my hand as hard as you can" .

一天，当帕特和迈克一起走在人行道上时，帕特把手放在一堵坚固的砖墙上说：“迈克，使劲打我的手”。