二甲苯苯环上的一溴代物有6种同分异构体，这些一溴代物与生成它的对应二甲苯的熔点分别列表如下：
| 一溴代二甲苯 |
234°C |
206°C |
213.8°C |
204°C |
214.5°C |
205°C |
| 对应二甲苯 |
13°C |
－54°C |
－27°C |
－54°C |
－27°C |
－54°C |
由表内数据可以推断，熔点为234°C的一溴代二甲苯的结构简式为 ，熔点为－54°C的二甲苯的名称为 。
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 |