The students are having a science class. They're 1 Miss Li. She is telling them about 2 and some students write in their notebooks. After that, she 3 , "Boys and girls! Can you tell me what water is 4 ?" But after two 5 , no one answers her. Miss Li isn't 6 . "Why don't you answer my 7 ? Do you forget all I teach you?"
Then a boy says, "Miss Li, you say water has no 8 . But when I 9 my hands in it, the water is black." All the students laugh.
Then a girl says, "Miss Li, where can we 10 water if (如果) we can't see it?"
"11 do you say that?" Miss Li asks.
"Because the water in the 12 next to my bouse is always black," answers the girl.
"I'm 13 about that," says Miss Li. "Our water is 14 now. All of us must 15 to make it clean." The students all think she is right.
