Strike

Today, when I was on the bus to school in the morning, I saw someone stood beside the road. Both of them had a board wrote “On Strike” held in front of them. Some of them waved to the bus and they looked pleasant. I thought they might be in some kind of party, or maybe something dangerous happened since there was “Strike” on the board. As far as I know, the word “Strike” may mean what we are doing in the game “Counter-Strike”.