25+40=____
36-20=____
48+30=____
25+4=____
某工厂计划两年把产品的成本下降19%,则平均每年下降( )
要求:说明所需的辅助器材,并写出简要的操作步骤。
器材:____。
步骤:____。
We should never give up ___________ others. Sometimes helping others means helping ourselves.