Unit7 How much are these socks?（必背作文）

【必背短文:谈一次购物经历》
Dear Mary,
I'm very glad to write this e-mail about my shopping experience in your shop.
I go shopping with my mother at your store. I buy a pair of shoes for 20 yuan. The pair of shoes is red because red is my favourite color. I also buy a purple dress, because it is really cheap. I spend only 30 yuan buying it. Besides, I buy two pairs of shorts for the school sports meeting. They are 25 yuan. The clothes in the store are really good and the sellers are very kind to us.
Both my mother and I are very happy!