21. 考虑到问题的严重性，在事态进一步恶化之前，必须采取有效的措施。

In view of the seriousness of this problem, effective measures should be taken before things get worse.

22. 在过去的几十年，先进的医疗技术已经使得人们比过去活的时间更长成为可能。

In the last decades, advances in medical technology have made it possible for people to live longer than in the past.

23. 我们应该不遗余力地美化我们的环境。

We should spare no effort to beautify our environment.

24. 人们相信拥有计算机技术可以获得更多工作或提升的机会。

People believe that computer skills will enhance their job opportunities or promotion opportunities.

25. 我同意后者，有如下理由：

For my part, I agree with the latter opinion for the following reasons:

26. 在给出我的观点之前，我想看看双方的观点是重要的。

Before giving my opinion, I think it is important to look at the arguments on both sides.

27. 这一观点正受到越来越多人的质疑。

This view is now being questioned by more and more people.

28. 环境学家指出：持续增加的污染不仅会导致像全球变暖这样严重的问题，而且还将威胁到人类在这个星球的生存。

Environmental experts point out that increasing pollution not only causes serious problems such as global warming but also could threaten to end human life on our planet.

29. 考虑到这些严重的状况，我们比以往任何时候更需要像自行车这样的环保型交通工具。

In view of such serious situation, environmental tools of transportation like bicycle are more important than any time before.

30 尽管自行车有许多明显的优点，但是它也存在它的问题。

Despite many obvious advantages of bicycle, it is not without its problem.