这里主要的区别在于冠词a,the用法的区别定冠词the的用法.1.表示上文已经提到过的人或者物,或特指某人或某物.例如 give me the book.2.表示这世上独一无二的东西.例如 the sun,the moon,the air.3.对两个人或物进行比较时起特定作用的比较级前.例如 He is the tallest student in our class.All the better.4.用在形容词最高级、序数词及last,next,only,same,right,wrong前.5.用在江河、海洋、山川、群岛、港湾等名词前.注意:湖名前一般不加冠词.不定冠词A/AN的用法.1.泛指人或物.2.表示one/every.3.用在抽象名词前.表示一种、一类、这种等等.4.用在物质名词前.例如 A glass,a iron,an apple.而在a second language中,第二外语不是特指,只是指一门第二外语,所以用冠词a即可,比如The students in this school learn English as a second language.the second language必须放在一定语境内,比如English is the second language of this country.所以用a secound language