i-21+2i=(i-2)(1-2i)(1+2i)(1-2i)=i-2+2+4i5=i
故选A
此题要求改正所给短文中的错误。短文中有10处错误，每句最多有两处。错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏词符号（）,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。
Dear editor,
I’m a college student and I’ll graduating in half a year. I’m very worried about my future, because find a good job is so much difficult. At the moment, my parents want me to be a teacher, and I don’t like that idea. During my holiday break, I work part-time as a tour guide in my hometown. I liked job very much. But my parents didn’t agree with me. They thought the work was difficulty, even though one could make a lot of money. That is the most important to me is that being a tour guide won’t take me far from home. I always consider what my parents say, but it’s hard for me to take a decision. Could you give me some suggestion?
下列疾病最易引起胸膜改变的是（）
A.肺结核
B.大叶性肺炎
C.麻疹肺炎
D.急性血吸虫肺炎
E.肺组织细胞增多症
）,并在此符号下面写出该加的词。