addition /əˈdiʃəｎ/ n. 1.［u］加法，增加(有时可加不定冠词)： The sign “+” stands for addition. 符号“+”代表加法。2.［c］增加的人或东西，附加物：He has another addition to his family. 他家里又添了个小孩。 in addition 此外，还：Aunt Mary gave us sandwiches for picnic and a bag of cookies in addition.玛丽阿姨为我们的远足准备了三明治外加一袋甜饼。in addition to… 除了…之外：In addition to his salary, he has a bonus of 300 yuan per month. 除工资外，他每月还有300元奖金。
additional /əˈdiʃənəl/ adj. 附加的，另外的，追加的：This was an additional proof of his ignorance. 这是他无知的又一条证据。An additional charge is made for heavy bags. 重量大的口袋要额外收费。
