"a" is a small letter whereas "A" is a capital letter

Hello smallqiang your question is "What is the difference between "a" and "A" ? This is an english article and there is no difference "A" like that is a capital letter. It is used in general to start a sentence like all the capital letters or to start to write a "proper name". The meaning is the same. eg : a book in a sentence : "A book is on the table". Hope it is clearer...

Hello smallqiong, a consists of 2 curves, while A makes up 3 lines ;)

The difference between A and a is its application. A, capital, it is used in the first place of a sentence, or after the period. a, small letter used in any places of the sentence. For example: A man and a pen. Is it a man? No, it is a pen.

what more can I say? they're of the same meaning. :)