题目内容：

语法填空

阅读下面材料，在空白处填入适当的内容(1)个单词或括号内的单词的正确形式。

Lin:  Grandpa, why is water called liquid (液体) gold?

Grandpa: That’s 1._________ it’s very precious. Water resources are limited (有限的), you know.

Lin:  But there’s a lot of water in the sea.

Grandpa: That’s 2._______ (salt) water. We can neither drink it nor take 3._____ shower with it.

Lin:  I see. The book says water is sometimes dangerous. Does that mean floods (洪水)?

Grandpa: You’re right. Floods are harmful and destructive. They can cause huge economic damage. When a flood 4.______ (happen), people are killed, houses are washed 5.________, and roads are 6.________ (destroy).

Lin:  How terrible! What about earthquakes? Are they as harmful as floods?

Grandpa: Yes. You can never imagine how strong earthquakes are. The Wenchuan earthquake in 2008 7.______ destroyed the whole city.

Lin:  Wow! What happened to the people after that earthquake ?

Grandpa: They became 8.__________ (home). But the Red Cross cared for9.______. And people around the world all gave away their 10._________ (donate) like money, food, water and medicine to them.

Lin:  I hope to be a volunteer one day to help those people in need.

Grandpa: There’s a good girl.