A:英国伦敦
B:法国巴黎
C:俄国彼得格勒
D:苏联莫斯科
请根据对话选词填空
ducks quiet nature park people buildings
There is a____. The nature park is____. There aren't many ____. There aren't many tall____. There are some animals. They are____and rabbits.
若(a+2)2+|b-a|=0,求代数式a3-3a2b+3ab2-b3的值。
人工辅助授粉方法是先____,然后涂抹或倾撒在同种植物的____上.