Common 用于是通常的、常發(fā)生的、廣泛使用或眾所周知的：
a common problem;
共同的問題；
a common thief;
普通的小偷；
the common dandelion.The term also suggests lack of distinction and can imply coarseness or crudeness:
普通的蒲公英.此詞條也暗示缺乏區(qū)別并能意指粗劣或未加工：
drank wine of the commonest sort;
最為普遍的飲用葡萄酒；
had a very common look about him.
他有著很普通的外表.
Ordinary describes what is of the usual kind and is not distinguished in any way from others.In the latter sense it is sometimes derogatory:
Ordinary 指種類普通且不能從其他中加以區(qū)別的.在后一意義上,它有時是貶義的：
A ballpoint pen is adequate for most ordinary purposes.
原珠筆適合最普通的用途.
The violinist gave a very ordinary performance marked by an occasional memory lapse.
小提琴手因偶然記憶失誤表現(xiàn)很平常.
Normal stresses adherence to an established standard,model,or pattern:
Normal 強(qiáng)調(diào)符合已建立的標(biāo)準(zhǔn)、模型或方式：
normal body temperature;
正常體溫；
normal curiosity.
正常的好奇心.