从下面的方框中选择一个适当词填空，并将其正确形式写在句中横线上，每空一词，只用一次。

beautiful  lend  smoke  much  kindness  energy  protect  luck  invent twenty-one

This year is 2012. We are living in the __________Century. 
---“Honey, I need to refresh myself. Do you mind my ____ in the living room？
---No way!”
Computer is one of greatest _____，I can’t imagine what our life would be without it.
---Mr. Sun, could you give me some advice on how to improve my spoken English?
-----The____ practice you make, the better your spoken English will be.
It’s _____ of you to help the people in need.
A low-carbon lifestyle has an effect on our daily life. People should pay more attention to saving _____.
There was a big fire in the office yesterday. _______，all the people were saved.
Our goal is ______ our environment from being destroyed.
On April 14th, an earthquake hit Yushu and destroyed its _______completely.
—It’s a great pity.
Tomorrow Tom will return the book I _____ to him. .