实验室需配置一种仅含四种离子（不考虑水电离出来的离子）的无色混合溶液，且在混合物溶液中四种离子的浓度均为1mol/L。下列四个选项中能达到此目的的是
| A．Na+、K+、SO42－、Cl－ | B．Cu2+、K+、SO42－、NO3－ |
| C．H+、K+、HCO3－、Cl－ | D．Mg2+、Na+、Cl－、SO42－ |
It’s high time you had your hair cut ; it’s getting _______ . 
| A．too much long | B．much too long |
C．long too much | D．too long much |
My friend showed me round the town, ______ was very kind of him. 
| A．which | B．that | C．where | D．it |
They use computers to keep the traffic _______ smoothly.
| A．being run | B．run | C．to run | D．running |
If you leave the club, you will not be_____back in .
| A．received | B．admitted | C．turned | D．moved |
What I need is_____ book that contains ______ABC of oil painting.
| A．a; 不填 | B．the; 不填 | C．the; an | D．a ; the |