19.In short, …are the major problems to be solved to…

　　例句：In short, shortage of water, decrease of fertile fields and environmental pollution are the major problems to be solved to increase grain production。

　　20.Who is to say that…?

　　例句：Who is to say that our scientists may not provide a better theory?

　　三、常用的过渡句式

　　1. Although lots of people follow the fashion/trend, I still set my heart on…

　　例句：Although lots of people follow the fashion, I still set my heart on its negative effect on our society。

　　2. For one thing… For another… As a third benefit/disadvantage…

　　例句：For one thing, some excellent students can take full advantage of the holiday to awaken their personal interests such as painting, sightseeing and so on. For another, it can provide more chances for some poor students to help make two ends meet and to get prepared for the future by taking part-time jobs. As a third benefit, for those who are far from good at a certain subject, there is a golden opportunity of catching up with other。

　　3.It is no easy/simple task/job to furnish/identify/find every reason/cause for sth., but/while, on the whole, two/some factors shout louder/ weigh heavier than others/stand out from others。

　　例句：It is no easy job to find every reason for the increase in the number of teenagers who run away from their homes, but, on the whole, two factors shout louder than others. First of all, …. Second, …

　　4.In contrast with the drawbacks/demerits/flaws of sth., sth. else can serve as a better step/move/advance in the right direction/toward the solution for the problem of…

　　例句：In contrast with the drawbacks caused by nuclear power, the solar power can serve as a better move toward the solution for the problem of energy crisis。

　　5.It is true/obvious that sth can’t compete/be compared with sth else in…, but sth still enjoys/secures/possesses distinct/substantial advantage over sth else。

　　例句：It is obvious that radio cannot compete with television in visuality, but it still possesses substantial advantages over television. (One of these is…Another…Still another…)

　　6.But if…, it is easy/not difficult/hard to see/find/discover that…

　　例句：But if they adjust their frame of mind a little in the other direction, it is not hard for them to find that life is just as promising as before。

　　7.Superficially/On the surface/At first glance/In appearance, the issue in question seems…. But in fact/in substance/on close examination, …

　　例句：At first glance, the western-type democracy seems superior to any other types. But on close examination, it does not entitle every citizen of the same nation to the equal freedom to act。

　　8.Those in favor of the issue in question argue/contend/hold/maintain/claim that…. But what they fail to consider/analyze/see/find out is that…