请修改以下短文：文中共有10处语言错误，错误涉及一个单词的增加、删除或修改。 增加：在缺词处加一个漏字符号（∧），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。 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 couldn't believe my ears when I heard my name calling. I was chosen to play the leading role in the play, that was my dream. As a shy and thin girl, I was used to be quite afraid of speaking in the public. But my parents and teachers always encourage me to do so. Now I have changed great. In class, I am often the first one to stand up and answer questions even if I may take some mistakes. No pains, no gains. Now I am always brave enough overcome the difficulty in my heart and have changed in a lively girl. But my experience shows that we should not be afraid of losing faces and only in this way can we make progresses.
的公比
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成等差数列，则
