A British design company have launched a new product to help children concentrate at school--pre-chewed pencils.
一家英国设计公司最近推出一款新产品，以帮助孩子们集中精力学习，它就是“被咬过的铅笔”。
2
However, when the technology of bacterial pre-oxidation and cyanide leaching for flotation concentrate of gold is used, the leaching rate of 92.73% is reached.
对浮选金精矿采用细菌预氧化—氰化浸出工艺，金浸出率可达到92.73%。
3
The concentrate blending plant regulates the fume volume from pre-drying fume exhaust system via controlling the opening of shutter valve.