用所给动词的适当形式填空。

The students(1) _____________ (have)their chemistry class．Miss Li(2) ________(tell)what water was like．After that，she(3) _______________(ask)her students，“What’s water?”No one said anything．After a minute，Miss Li asked again，“Why don’t you answer my question？(4) ________________ I(5) ________________(not tell)you what water is like?”

    Just then．a boy put up his hand and(6) ________ (say)，“Miss Li．you(7) __________(tell)us that water(8) ___________ (have)no color and no smell．But where can we find such kind of water？The water in the river behind my house is always black and it has a bad smell．”most of the children(9) ___________ (agree)with him．

     “I’m sorry．children．”said the teacher，“Our water(10) ____________(get)dirtier and dirtier．That’s a problem．”