3.表明作者的观点、态度 

1)Introducing( or emphasizing) further evidence: 

moreover, furthermore, in addition, what’s more, as well, etc. 

2)Cause: 

because (of), since, owing to, on account of, due to, as a result of, etc. 

3)Effect: 

as a result, hence, therefore, consequently, thus, so, etc. 

4)Contrasting: 

in / by contrast, on the contrary, on the other hand, nevertheless, whereas, while, yet, however, but, etc. 

5)Comparison: 

in like manner, likewise, in the same way, similarly, in comparison with, etc. 

6)Purpose: 

to this end, for this purpose, with this in mind, in order to, so that, etc. 

7)Intensification: 

indeed, in fact, in any event / case, at no time, to tell the truth, etc.