(误)He neither speaks English nor French.
(正)He speaks neither English nor French.（either…or，not only…but also等对等相关连词所连接的部份应是相同词性或起相同作用。）
(误)For I did not feel well today, decided to stay at home.
(正)I decided to stay at home for I did not feel well today.（对等连词for连接两个对等的句子时不可放在句首。）
(误)Either you or I are wrong.
(正)Either you or I am wrong.（在含有either…or的句子中，谓语动词的数由较近的主语决定。）
(误)Although he is very rich, but he is not happy.
(正)Although he is very rich, he is not happy.（though或although放在字句首时，本身就具有虽然…但是的意思，不可和but连用。）
(误)I have never been to London and Paris.
(正)I have never been to London or Paris.（在否定句中，对等连词一般不用and，而用or。）
(误)I shall speak to him until he apologizes.
(正)I shan't speak to him until he apologizes.（not…until表示到…时候才，在此句中speak的动作要等到他道歉时才发生。）
(误)Because I wanted to learn English, so I bought a dictionary.
(正)Because I wanted to learn English, I bought a dictionary.（because本身就具有因为…所以的意思，不可再和so连用。）
---------By Bao Zhao