增加：在缺词出加一个漏字符号（∧），并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
I hardly remember my grandmother. She used to holding me on her knees and sing old songs. I was only four when she passes away. She is just a distant memory for me now.
I remember my grandfather very much. He was tall, with broad shoulder and a beard that turned from black toward gray over the years. He had a deep voice, which set himself apart from others in our small town, he was strong and powerful. In a fact, he even scared my classmates away during they came over to play or do homework with me. However, he was the gentlest man I have never known.
