Turn left ______________ the traffic lights. [ ]
A. at
B. in
C. on
答案：A
My mother is going to America ____________ plane. [ ]
A. on
B. by
C. take
煤气柜检修用空气置换惰性气体合格后,放散管或人孔应处于敞开状态,防止气温变化产生超压。（）
