用括号中所给单词的适当形式填空
Mark was the only student that was ____ to attend the meeting．（choose）
It's important for everyone to know how to ask for help ． （polite）
Grace loves dancing． She wants to be a when she grows up． （dance）
将划线部分的英语译成汉语，注意使用适当的形式．
Building a beautiful countryside is what we hope for and what we'll work hard for．
将划线部分的英语译成汉语，注意使用适当的形式．
I like taking a walk in the bamboo forest because the air there is clean and fresh．
根据句意，用括号中所给词的适当形式填空，
To better understand the habits of elephants， the government spent a lot of money doing （科学研究）．