下列式子为最简二次根式的是（　　）.

增加：在缺词处加一个漏子符号（∧)，并在此符号下面写出该加的词。

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。

注意：1.每处错误及其修改均仅限一词：2.只允许修改10处，多者（从第11处起）不计分。

    I had a interesting dream last night. I dreamed that I took part in a race. At first, I could not to run very fast and fell behind. So I didn’t lose heart and kept running. All the students on the playground cheer me on," Come on!” I was so encouraged that I ran faster and fast till I caught up all the other runners. I felt as if flying like a superman. In the end, I get to the finishing line first. I won the race. I felt very proudly of myself. Many of my classmate threw me up into the air. Just at that time I woke up and found me still in bed!