成语

当社会突飞猛进的时，我们的做梦成现实。
当经济卷土重来的时，我们的心情越来越高兴
当你的敌人要杀死你的时，我们应该韬光养晦

when society advances (in technology), our pipe dreams become reality
when the economy makes a comeback, our mood becomes happ(ier)
when your enemy wants to kill you, we have to conceal our strengths