1N-COUNT (象征共产主义或社会主义的)红旗;(示意危险或停止的)红旗 A red flag is a flag that is red in colour and is used as a symbol to represent communism and socialism or to indicate danger or as a sign that you should stop. (象征共产主义或社会主义的)红旗;(示意危险或停止的)红旗
They waved red flags and shouted, 'Lenin, yes'.
他们挥舞着红旗高喊:“列宁,万岁!”
Then the rain came and the red flag went up to signal a halt.
然后下雨了,红旗升起示意暂停。
2N-COUNT 危险信号;预警 If you refer to something as a red flag, you mean that it acts as a danger signal. 危险信号;预警
The abnormal bleeding is your body's own red flag of danger.