已知$x,y$为实数,且$\sqrt{x-1}+3{\left(y-2\right)}^2=0$,则$x-y$的值为（    ）

填入下列文段空白处的词语，最恰当的一组是（    ）

   乐音在基本确定了音高的范围后，有规律的声音节奏或声音组合   ①  成了让人产生美感的第一要素。   ②   声音仅仅含有节奏和有序性，  ③   不能成为“好声音”，钟表的“滴答”声、音乐节拍器的摇摆是最精准的节奏声音，  ④   它却无法给人以美感，  ⑤   会带来厌烦。  ⑥  ，为了使美好的声音成为艺术，还必须具备下一个条件：声音变化的丰富性。

① How many books do you have?____     A. I bought a lot of books.

② What are the rabbits doing?____     B. They are onions.

③ Can you play the piano? ____     C. I have twenty books.

④ What did you do last Sunday? ____     D. They are jumping.

⑤ What are these?____     E. Yes, I can.