对于锌、铜和稀硫酸组成的原电池(如右图),下列有关说法正确的是( )①Zn是负极 ②电子由Zn经外电路流向Cu③Zn -2e-==Zn2+ ④H+在溶液中由Cu棒向Zn棒迁移
It’s high time you had your hair cut ; it’s getting _______ .
My friend showed me round the town, ______ was very kind of him.
They use computers to keep the traffic _______ smoothly.
If you leave the club, you will not be_____back in .
What I need is_____ book that contains ______ABC of oil painting.