单选题 · 选择一个答案
What does the yellow traffic-signal warning sign on the left mean?
图中左侧黄色交通信号灯警告牌表示什么？
Traffic signals are ahead: observe them and prepare to stop as required.
前方有交通信号灯，应观察信号并准备按要求停车。
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The warning neither fixes their distance at 50–100 metres nor says they are faulty.
警告牌提示前方危险或交通控制，不单凭该图案保证信号灯必在50至100米处，也不表示信号灯已经故障。