Sample linking sentence

To link sentence, I collect some linking sentence as follows:

Analyzed style
introduction--
' This, as far as I am concerned, can be ascribed to the following causes.';
' The issue, however, though having caught much attention from sociologists, defies any solution unless its causes are thoroughly investigated.';
' As it has affected social stability, it is urgent to investigate the causes of the tendency and find solutions to the problem.'
Body--
' A most obvious cause of the problem is that ...';
' Another contributing factor is that ...';
' Last but not least ... is also responsible for the problem in question.';
Conclusion--
' In view of the above, I think some urgent measures need to be taken to solve this problem.';
' In view of the above, I would recommend that some urgent steps should be taken to put an end to this serious problem.';
' Solutions to the problem have to be devised in light of the causes.'

Comparative style
Reference structure:
1.
...I would like to voice my opinions as to the pros and cons of ...
The advantages of ... are rather obvious. In the first place... In the second place... In addition...
However, it cannot be denied that ... also has its drawbacks. As is known to all ... Furthermore.. Last but not least ...
The above discussion brings us to a conclusions that ... has both the merits and demerits. What we must do is to make sure that the positive effects are encouraged and the negative ones are avoided as far as possible.
2.
There have been discussions as to the advantages and disadvantages of ... for a long time. Many people have, on different occasions, voiced their opinions, which understandably vary from one to another. I would like to discuss the pros and cons of ... in the following.
There is no denying that ... has a lot of merits. First of all ... In addition ... Furthermore ... However, as an old saying goes, 'Every coin has two sides.' ... has its obvious disadvantages. In the first place ... In the second place ... Worst of all ...
All in all ... has both the merits and demerits. We should try our utmost to bring its demerits to the minimum.

Critical style
This kind of topic often follows questions like these:
(1) Do you agree or disagree?
(2) To what extent do you agree or disagree?
(3) What is your opinion?
If you agree, then follow sentence may be usefull:
Personally I agree with this opinion for the following reason.
I agree with the prevalent view on the following grounds.
In my opinion ... is well grounded.
As far as I am concerned, this popular opinion is supportable.
Personally, I think they are right.
If you disagree, then follow sentence may be usefull:
This opinion, however, seems untenable to me.
In my view, this worry is groundless.
From my point of view, this opinion is simply untenable.
For my part, there is no need for such worries.
Agree or disagree to some extent:
However, I find it hard to agree fully with this opinion.
Although many people are behind this stance, I find it hard for me to agree with this opinion fully.

The reference sentenses above just show you what kind of answers it should be. In order to get it become your own sentences, you should read and practise more frequently.