某烟气脱硫的工艺不仅能消除SO2,还能将其转化为石膏(CaSO4•2H2O)等产品,实现“变废为宝”.主要物质转化关系如下:
根据如图分析,下列说法正确的是( )
When you see an English film or talk with native speakers, observe their facial expressions and g____.