某原子的相对原子质量是M，核外电子总数为N，则该原子的中子数为（  ）

补全对话

从方框中选择最佳选项完成对话。

A. Yes, I do.

B. He was Austrian, wasn’t he?

C. Who is your favourite Western classical composer?

D. Yes, of course, I am. I love it, and I also listen to Chinese pop music. It’s wonderful.

E. I didn’t know that.

Jack: You like rock music, don’t you?

Lucy: ____ 

Jack: You are interested in Western music, aren’t you?

Lucy: ____ 

Jack: Me too. I like it very much just like you.

Lucy:____ 

Jack: Strauss. His music is very beautiful.

Lucy: ____ 

Jack: No, he was born in Austria, but he is a Frenchman.

Lucy: Really? ____ 

128÷4=

417×33=

285÷5=（验算）