有关原电池的判断正确的是（ ）
| A．比较活泼的金属一定做负极，活泼性较弱的金属一定做正极 |
| B．原电池的正、负极材料不一定都参与反应 |
| C．原电池的正极在放电后质量一定增加 |
| D．原电池的正极是电子流 |
—— 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 |
If you leave the club, you will not be_____back in .
| A．received | B．admitted | C．turned | D．moved |