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【单选题】
吹笛子时，人听到美妙的笛声是由于
[ ]
A.
气柱的振动产生了声音
B.
竹笛的振动产生了声音
C.
人声带的振动产生了声音
D.
竹笛周围的空气振动产生了声音
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Some of the most popular attractions across America are the many free concerts offered to public throughout the year. These involve not only amateur performers, but professional artists as well. The p...
A.
have the necessary facilities
B.
call attract more visitors
C.
want to serve the public
D.
are in a position to invite musicians
【单选题】Some of the most popular attractions across America are the many free concerts offered to public throughout the year．These involve not only amateur performers, but professional artists as well．The pub...
A.
have the necessary facilities
B.
call attract more visitors
C.
want to serve the public
D.
are in a position to invite musicians