1)表层次: 
first/firstly /to begin with /in the first place
second/secondly/furthermore
third/thirdly/what is more/besides
 in addtion /finally 

2)表转折:
by contrast /although /though/ yet
at the same time /but 
despite/the fact that
even so /in contrast 
nevertheless /even though
 for all that /notwithstanding 
on the contrary/ however in spite of
on the other hand /otherwise 
instead /still /regardless 

3)表因果: 
therfore /consequently 
because of/ for the reason
thus/ hence /due to 
owing to /so /accordingly 
thanks to /on this account /since /as 
on that account /in this way /for /as a result 
as a consequence 

4)表让步: 
still /nevertheless/in spite of /all the same 
of course /despite /even so /after all