用食用白醋(醋酸浓度约为1 mol/L)进行下列实验,能证明醋酸为弱酸的是
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.
Jenny nearly missed the flight______ doing too much shopping.