A：under
B：in
C：to
D：of
It is ____(polite) to stare at others in public places.
日常生活中对微生物的应用非常普遍，下列相关说法正确的是（ ）
下列代数式中，值一定是正数的是（ ）
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.
