What BPA is and where it's used?BPA is a manmade industrial chemical. It's a key building block in polycarbonate (no. 7) plastic, which is used to make a wide variety of products: water and juice b...

小时候，相信大家都听过《神笔马良》的故事，毛笔一挥，画中的东西就活了起来，很是神奇。能让画变成现实也只有在童话