A:
B:
C:
D:
A.Here you are.
B.Yes, I want a bird.
C.That's right.
D.I'm six.
E.How nice!
(____)1.Two and three is five.
(____)2.This doll is for you.
(____)3.I want a pencil.
(____)4.How old are you?
(____)5.Please make a wish, Mike.
小明自己制作了一个哨子,如图所示,在筷子上缠一些棉花,做成一个活塞,用水蘸湿棉花后插入两端开口的塑料管.吹管的上端,可以发出悦耳的哨声.这哨声是由 ____产生的.上下推拉活塞,可以改变声音的 ____