下列离子方程式正确的是（ ）
| A．等物质的量浓度的FeBr2和CuCl2混合溶液用惰性电极电解最初发生： Cu 2++ 2Br－  Cu +Br2 |
| B．碳酸氢镁溶液中加入足量的烧碱溶液： Mg2+ + 2HCO3- + 2OH-= MgCO3↓+ CO32- + 2H2O |
| C．Fe(NO3)3的酸性溶液中通入足量硫化氢：2Fe3+＋H2S===2Fe2+＋S↓＋2H+ |
| D．H218O中投入Na2O2：4H218O＋O22－===2H2O＋4OH－＋18O2↑ |
I can’t leave. She told me that I ______ stay here until she comes back.
| A．can | B．must | C．will | D．may |
—— Do you mind my opening the window? It’s a bit hot in here.
—— ______ , as a matter of fact
| A．Go ahead | B．Yes, my pleasure |
C．Yes, I do | D．Come on |
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 |