下列符号表示两个分子的是（   ）

某哺乳动物的直毛（B）对卷毛（b）为显性，黑色（C）对白色（c）为显性（这两对基因分别位于不同对的同源染色体上）．基因型为BbCc的个体与“个体X”交配，子代的表现型有直毛黑色、卷毛黑色、直毛白色和卷毛白色，它们之间的比为3：3：1：1，“个体X”的基因型为（　　）

随着我国经济的增长，我国现行的个人所得税起征点第三次调整，由现行2000元上调至3500元。其中蕴含的哲学道理是：                             

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅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。
    Last summer I go to America and studied at a language school. I had many wonderful experience, but I also had a sad one. One day, the school held party , where I invited to talk about Chongqing. After that they asked me a lot of things about China. But I couldn't explain them with English clearly. I felt sadly. I learned a lesson from this experience. I have already studied English for eight years, I can't use it very good. I must work hard to improve my spoken English so that I will not be able to communicate freely with foreigners. I hope I can be a bridge between China and others countries in the future.

单词拼写 (共10小题；每小题1分，满分10分)
根据下列句子及所给汉语注释，在句子右边的横线上， 写出空缺处各单词的正确形式。每空只写一词。