为了减少大气污染，许多城市推广清洁燃料．目前使用的清洁燃料主要有两类，一类是压缩天然气，另一类是液化石油气，这两类燃料的主要成分都是 ( )
| A．碳水化合物 | B．碳氢化合物 | C．氢气 | D．醇类 |
—— 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 |