下列说法不正确的是( )
| A．同种元素的质子数必定相同 |
| B．质子数相同，电子数也相同的粒子，不可能是一种分子和一种离子 |
| C．原子核都是由质子和中子构成的 |
| D．电子数相同的粒子不一定是同一种元素 |
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 |