决策的科学化、民主化是实行民主集中制的重要环节,是社会主义民主政治建设的重要任务。( )
参考答案:对
When first____ to the market, these products enjoyed great success.
A.being introduced
B.having introduced
C.introduced
D.introducing
挖掘机的铲斗宜选用()。
A.ICrl8Ni9
B.40Cr
C.20CrMnTi
D.ZGMn13