Did you not understand what I said to you? -Sorry, I didn’t (vì trc trợ động từ thì động từ giữ nguyên)
The dress was pink and little white flowers on it (vì miêu tả thứ trên vật j đó thì dùng vs with)
My mother bought for me a nice schoolbag on the occasion of a new school year (bỏ từ for đi vì buy ko dùng vs for)

Did you not understand what I said to you? -Sorry, I didn’t
=> Did you not understand what I said to you? -Sorry, I didn’t 
The dress was pink and little white flowers on it
The dress was pink and little white flowers on it
My mother bought for me a nice schoolbag on the occasion of a new school year
My mother bought for me a nice schoolbag on the occasion of a new school year