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 |