當therefore在整句中時，一般不放句末，放在句首后要有逗號，放在句中時前后都要有逗號。

　　He was the only candidate; therefore, he was elected.

　　他是唯一的候選人，因此，他當選了。

　　Many fast food restaurant ,therefore,have red furniture or walls.

　　因此，許多快餐店都有紅色的家具或墻壁。

　　當therefore用在分句中時，即一個句子一部分表示原因一部分表示結(jié)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。

　　I had a headache，therefore I could not go to your party.

　　我頭痛，所以不能去參加你的聚會。

　　I was ill, and therefore I could not come.

　　我病了,所以沒能來。

　　We do not have enough money. Therefore we can not afford to buy the new car.

　　我們的錢不夠,因此買不成這輛新車。