浓度为70%的酒精溶液500克与浓度为50%的酒精溶液300克,混合后所得到的酒精溶液的浓度是多少( )
A.54.2%
B.62.5%
C.34.5%
D.60%
参考答案:B
is no doubt his bad performance has influenced his development.[ ]
A.It;that
B.There;that
C.It;whether
D.There;whether
在有串联补偿电容器的线路上短路暂态过程会出现低频分量,在有并联电抗器是还会产生2个衰减很慢的非周期自由分量。