阅读下列短文，从每小题的三个选项中选出最佳选项。

    Hello, my name's Kitty. I have a big family. My grandparents are old. They are thin.

    David is my father. He is fat. He is a policeman(警察). This is my mother. Her name is May. She's tall and thin. She is a nurse. John is my uncle. He has a pair of glasses. He is a doctor. He can help people. Sue is my aunt. She has big eyes. She likes kids. She is a teacher. I have one cousin. His name is Peter. John and Sue are his parents.

由于某种原因，某生物体内某条染色体上多了几个或少了几个基因，这种遗传物质的变化属于（  ）

补全对话：

①  What's your name? ____ 

②  Nice to meet you again. ____

③  How are you?____

④  Where are you from? ____

⑤  Good morning boys and girls.____

a.  My name is Amy.      b.  Fine, thank you.         c. Nice to meet you, too.

d. Good morning, Mr. Black    e.  I'm from the USA

从家到图书馆，爸爸用了$\frac{1}{4}$小时，兰兰用了0.4小时，（　　）走得比较快．