— Got your driving license?

— No. I ________ too busy to have enough practice, so I didn't take the driving test last week.[ ]

A. was  

B. am

C. have been  

D. had been

下列描述中，属于物质化学性质的是（　　）

A．水是无色的液体

B．铁丝在氧气中能燃烧

C．酒精在空气中易挥发

D．氯化钠的熔点是801℃