如图所示,用手拨动塑料尺,发出的声音是由塑料尺____产生的。塑料尺振幅越大,声音的____越大。若改变塑料尺伸出桌面的长度,会使声音的____发生改变。
A. You're welcome.
B. What shape would you like?
C. I'd like some cherries, too.
D. What kind of pudding would you like?
E. Yes. I want to buy a pudding.
A: Can I help you?
B:____
A:____
B: I'd like a chocolate pudding.
B: I'd like a heart-shaped pudding.
A: Anything else?
B:____How much are they?
A: 70 yuan.
B: Here is the money.
A: Thank you.
下列对东南亚的开发和繁荣作出了巨大贡献的是( )
如图是探究“阻力对物体运动的影响”的过程.根据图中情景可以判断以下说法正确是( )