若实数a满足a2-2a=3，则3a2-6a-8的值为（ ）。

Traffic conditions in Beijing________for decades. At first people only complained about jams during rush hours,but today every hour is rush hour. [ ]

A. is worsening            

B. have worsened

C. have been worsening      

D. worsened

Allen followed his customer across the yard and stood on the step of the house,        two shopping bags. 

A．lifted

B．having lifted

C．to lift

D．lifting

墙上挂着一块长30厘米的平面镜，小明站在镜子前1.5米处，这时他正好可以看到身后的一根木杆，木杆高2米，那么这根木杆离人的距离应该是（　　）

小儿指纹色紫主证为（）。

A.燥

B.热

C.寒

D.滞

E.瘀

与固体物质溶解度无关的是（）。

A.温度

B.压强

C.溶剂量

D.溶液量