這幾個詞的區別大致可從以下幾方面去看：
1、therefore adv.因此, 所以=for that reason=consequently常用於連接兩個並列分句,其前加“and”或分號“；”.
He was ill, and therefore could not come. 他病了, 所以未能來.
He has broken his leg and therefore he can't walk.他摔壞了腿,因此不能走路了.
We do not have enough money. Therefore we cannot afford to buy the new car.我們的錢不夠,因此買不成這輛新車.
therefore用法:
therefore有兩種用法,一在整句中,一在分句中.therefore是副詞,但有時具有連詞作用.
一、整句中時一般不放句末,句首后要有逗號,句中1、按一般副詞使用2、做插入語（這兩個分得清吧）
eg.1、Therefore,we must learn English well.
2、They therefore can learn English well.
3、Many fast food restaurant ,therefore,have red furniture or walls.
二、用在分句中,即一個句子一部分表示原因一部分表示結果.
這時一般詞前要用分號,其后用不用逗號無所謂.若第二個分句前是逗號或無符號,則要注意therefore是副詞,和so不一樣,要保持句子完整,應用and therefore.
eg.1、I had a headache;therefore I could not go to your party.
2、I was ill,and therefore could not come.
3、These birds are very beautiful and therefore liked by many people.
2、so conj. adv因而, 所以, 結果是
It was late, so we went home. 天晚了, 所以我們就回家去了.
He was sick, so they were quiet.他病了,所以他們很安靜.
3、hence adv.因此, 從此
The town was built among the hills, hence the name Hilltown. 該城鎮修建在群山之中,故取名'山城'.
It is very late; hence you must go to bed.時間已經很晚了,因此你必須睡覺去.（記住前面是分號,而不是逗號）
4、then adv因此,就
Go into the cave, then they won't see you. 躲進洞里去,那他們就看不到你了.
5、accordingly adv.因此, 從而；所以,因此結果；因此（偶作連詞使用conj.）
He was asked to leave the city and accordingly he went.有人叫他離開該城市,所以他就走了.
You may arrange accordingly.你可以權宜處理.
Mr Foster has never been to China. Consequently / Hence he knows very little about it.福斯特先生從未去過中國,所以對中國了解得很少.
My car was broken down and consequently I was late. = in consequence
6、thus adv.如此,像這樣；因此；於是
He sold his farm and thus he had enough money for his journey.他賣掉了農場,這樣他就有足夠的錢旅行了.
There has been no rain — thus, the crops are drying.天沒下雨,因此庄稼要枯死了.
accordingly,consequently,hence,so,therefore,thus
這些連接副詞均有“因此，所以”之意。
accordingly書面用詞，強調根據某種原因而得出的結果，其前可用冒號或分號，但不用逗號。
consequently正式用詞，側重符合邏輯的結果。
hence較正式用詞，指接下來的東西是理所當然的必需的東西，但強調其重要性。
so用於比較隨便的場合，口語中多用。
therefore通常指引出一個推斷出的必然結論。 thus多用於書面語中，可與therefore換用。