徒步时听到响尾蛇的尾巴发出响声要立即后退。

If you hear the sound of a ___rattlesnake's tail while hiking, step back immediately.

那个谈判桌上全是危险人物，就像一窝随时会咬人的响尾蛇。

The negotiation table was filled with ___rattlesnakes ready to strike at any moment.