a和an用法顺口溜：不定冠词a和an,单数可数名词前;辅音若在词首发,词前只把a来加;元音若在词首放,词前an词不敢忘;不定冠词相当one,但不强调数观念;不定冠词很关键,四个所指记心间.(每指、泛指、类指和某指)。
扩展资料。
不定冠词a/an的用法：
不定冠词有两个，a 和 an。a用在辅音开头的'单词前面;an用于以元音开头的单词前。如：a book,an apple。具体用法如下：
1)表示“一个”、“某一个”、“ 每一”、“再一，又一”、或“同一，相同”等。
eg：
rome is not built in a day
a mr.smith is waiting for you at the school gate
he usually works eight hours a day
you can try it a second time if you fail
they are of an age./ birds of a feather flocks together
2)泛指某一类人或物，意为“任何一个，任一”
eg:
a square has four sides
3)当物质名词具体化表示“一(类、阵、份)”等;抽象名词具体化为“……的人或者事”时。
eg:
green tea is a wonderful tea
we don’t have much rain here,but last night we had a heavy rain
reading is a pleasure for me
the meeting is a great success
4)表示季节、月份、日期、三餐的名词，或表示世上独一无二的物体名词前有形容词修饰时：
eg:
we have a every cold winter last year
this happened on a rain sunday towards the end of may
we hope we can see a full moon tonight
5)源于动词的名词与take/have 连用时：
take a look;take a walk;have a break;have a visit to…。
扩展资料。
不定冠词a/an的用法：
不定冠词有两个，a 和 an。a用在辅音开头的'单词前面;an用于以元音开头的单词前。如：a book,an apple。具体用法如下：
1)表示“一个”、“某一个”、“ 每一”、“再一，又一”、或“同一，相同”等。
eg：
rome is not built in a day
a mr.smith is waiting for you at the school gate
he usually works eight hours a day
you can try it a second time if you fail
they are of an age./ birds of a feather flocks together
2)泛指某一类人或物，意为“任何一个，任一”
eg:
a square has four sides
3)当物质名词具体化表示“一(类、阵、份)”等;抽象名词具体化为“……的人或者事”时。
eg:
green tea is a wonderful tea
we don’t have much rain here,but last night we had a heavy rain
reading is a pleasure for me
the meeting is a great success
4)表示季节、月份、日期、三餐的名词，或表示世上独一无二的物体名词前有形容词修饰时：
eg:
we have a every cold winter last year
this happened on a rain sunday towards the end of may
we hope we can see a full moon tonight
5)源于动词的名词与take/have 连用时：
take a look;take a walk;have a break;have a visit to…。