常用的关联词分为十一大类：
1. Certainty
obviously，certainly，plainly，of course，undoubtedly
2. Contrast
however，on the other hand，despite，in spite of，though，although，but，on the contraryotherwise，yet，instead of，rather，whereas，nonetheless，even though，compared with，in contrast，alternatively
3. Condition
if，unless，whether，provided that，for，so that，whether，depending on
4. Definition
is，refers to，means，that is，consists of
5. Summary
in conclusion，in summary，lastly，finally，to sum up，to conclude，to recapitulate, in short
6. Example
for instance，one example，for example，just as，in particular，such as，name to illustrate
7. Reason
since，as，so，because(of)，due to，owing to，the reason why，in other words，leads to，
8. Time
before，since，as，until，meanwhile, at the moment，when，whenever，as soon as，just as
9.Additionin
addition，and，similarly，likewise, as well as，besides，furthermore，also，moreover，and then，too，not only ... but，even，besides this/that
10.Sequence
first(ly)，initially，second(ly) etc.，to begin with，then，next，arlier/later，after this/that following this/that，afterwards
11. Consequence
as a result，thus，so，therefore，constantly, it follows that，thereby，eventually，then，in that case，admittedly
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