根据句意，用单词的适当形式填空
It’s ________ (nature) that teenagers（青少年）may sometimes quarrel（争吵）with their parents.
We have  __________(little) snowfall this year than last year.
The tortoise is walking           .(slow)
Don’t forget to write down the _______(fishman) names.
You should prevent the hunters from  __________(kill) wild animals .