The students were having their chemistry（化学）class. Miss Li was telling the children what water was like. After that, she asked her students, “What’s water?” No one spoke for a few minutes．Miss Li asked again，“Why don’t you answer my question？Didn’t I tell you what water is like？”

Just then a boy put up his hand and said，“Miss Li，you told us that water has no color and no smell．But where to 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 agreed With him．

“I’m sorry，children．”said the teacher，“Our water is getting dirtier and dirtier．That’s a problem”．

小题1:The students were having their _______ class．

A．English

B．Chinese

C．chemistry

D．math小题2:Miss Li was telling the children what ______ was like．

A．water

B．air

C．earth

D．weather小题3:A boy said，“The water in the river behind my house is always ___．”

A．white

B．black

C．clean

D．clear小题4:Most of the children _______ the boy．

A．agreed with

B．wrote to

C．heard from

D．sent for

水泥混凝土试配强度计算涉及哪些因素( )。

A．混凝土设计强度等级
B．水泥强度等级
C．施工水平
D．强度保证率