caution

我会极度谨慎地对待他说的任何话。

I would treat anything he says with extreme ___caution.

操作重型机械时必须格外小心。

Extreme ___caution must be exercised when operating heavy machinery.

在飞机推回和发动机启动期间必须采取极端谨慎措施。

Extreme ___caution has to be taken during push-back and engine start.