red flag

名词 red flag:

1. a flag that serves as a warning signal
2. the emblem of socialist revolution
3. something that irritates or demands immediate action

1. It's time to shake out the red flag.
   是把这面红旗打开的时候了。
2. A red flag is a sign of danger.
   红旗是危险的信号。
3. A red flag slowly went up the pole.
   一面红旗徐徐升起。
4. The five-star red flag is fluttering in the wind.
   五星红旗迎风飘扬。