题干

小兰在观察提琴、吉他、二胡等弦乐器的弦振动时,猜测:即使在弦张紧程度相同的条件下,发声的音调还可能与弦的粗细、长短及弦的材料有关,于是好想通过实验来探究一下自己的猜想是否正确,下表是她在实验时控制的琴弦条件 。

     控制条件

编号

琴弦的材料

琴弦的长度

/cm

琴弦的横截

面积/mm2

A

20

0.3

B

20

0.7

C

尼龙丝

30

0.5

D

40

0.5

E

尼龙丝

40

0.5

(1)如果小兰想探究弦发声的音调与弦的材料的关系,你认为她应该选用编号为  ____ 的琴弦(只填字母代号);

(2)如果小兰想探究弦发声的音调与弦的长度的关系,你认为她应该选用编号为  ____ 的琴弦(只填字母代号) 。

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答案(点此获取答案解析)

D、E,C、E.

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 The song that has meant the most to me since I was the age of five,watching the movie Space Jam,is called “I Believe I Can Fly” by R.Kelly. Every time I listen to the song,it1methat as long as I believe,Ican be or do2I want in life even with a disability.

        I didn’t know much of what the song3a long time ago but as I grew older,Istill loved the song and started to listen to the4more and more.Every time I listen to it,Ithink about all the obstacles I have5.

       When I was little,Ihad to6a wheelchair because I have a disability.The doctors told mymother I had a slim7of ever walking but I was8to walkbecause I disliked that wheelchair.I knew that I had to believe in myself to9mygoal to walk someday.

       One day the doctor told my mother that he could make a(n)10that wouldhelp me walk.11when I was seven and one­half,I had my first surgery.

       I12the cast because it was a half body cast,witha bar in the middle of my legs.I was a very13kid so being in a bedfor six weeks,notbeing able to move,Ifelt horrible.I knew after all the14and the crying it would beworth15it in the long run.

16,at the age of eight,I got my cast off.I felt free when Ifinally17all the therapy (治疗)and learned how to18.

       The song19,“Isee me running through that open door.” That’s what I felt like.Like the songsays,“Thereare miracles in life I must achieve,butfirst I know it starts inside of me,oh...”I am one of the20in life.