已知酸性:H2SO4 > >H2CO3> > HCO3—,综合考虑反应物的转化率和原料成本等因素,将转变为的最佳方法是( )
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.