（）一般用于不需要辨别颜色和环境外观不重要的照明场合。
A.金属卤化物灯
B.荧光灯
C.紧凑型节能荧光灯
D.低压钠灯
参考答案：D
The other day, my brother drove his car down the street at _____ I thought was a dangerous speed.
A．as
B．which
C．what
D．that
网形拓扑结构的优点是：
