用所给的单词的适当形式填空什么意思?请完成下面几题!

用所给的单词的适当形式填空什么意思?请完成下面几题!
The monkey's tail is -----------(long)than the pig's.
The tiger is ---------(heavy)than the cat.
Cathy is----------（young)than her teacher.
Mike's legs are--------(short)than Yao ming's.
My father's hands are----------(big)than my gagy brother's.
Miss Wang is--------(thin)than Miss Chen.