Obviously,…. If we want to do something… , it is essential that…

　　显然,如果我们想做某事,很重要的是…

　　Only in this way can we… 只有这样,我们才能…

　　It must be realized that… 我们必须意识到…

　　预示后果:

　　Obviously, if we don’t control the problem, the chances are that… will lead us in danger. 很明显,如果我们不能控制这一问题,很有可能我们会陷入危险.

　　No doubt, unless we take effective measures, it is very likely that…

　　毫无疑问,除非我们采取有效措施,很可能会…

　　It is urgent that immediate measures should be taken to stop the situation.

　　很紧迫的是,应立即采取措施阻止这一事态的发展.