灯具布置，边行灯至场内的距离保持在（）.
A.l/2至l/4
B.l/2至l/5
C.l/3至l/2
D.l/4至l/5
参考答案：C
三方原则
After decades of effort, the city is still trying to _____ how to ban smoking in public places.
A．look through
B．get through
C．figure out
D．take out
