常用的关联词分为十大类：
一. Addition 此外
in addition ，and，similarly，likew瞚se，as well as，besides，furthermore，also，moreover，too ，not only ... but，even，besides this/that
二. Sequence 顺序
first ，initially，second etc.，to be瞘in with，then，next，earlier/later， following this/that，afterwards
三. Consequence 结果
as a result ，thus，so，therefore，consequently，it follows that，thereby，eventually，tn that case，admittedly
四. Contrast对比
however ，on the other hand，
despite，in spite of，though，although，but，on the contrary
otherwise ，yet，instead of，rather，whereas， nonetheless compared with，in contrast
五. Certainty 确定
obviously ，certainly，plainly，of course，undoubtedly
六. Condition 条件
if ，unless，whether，provided that，for，so that，whether，depending on
七. Time 时间
before ，since，as，until，meanwhile，at the moment，when，whenever，as soon as，just as
