下列有关熟石灰的说法不正确的是

A．在石灰窑中用石灰石经高温煅烧可制得熟石灰

B．农业上常用熟石灰来改良酸性土壤

C．熟石灰的溶解度随温度升高而减小

D．实验室可用熟石灰和纯碱(Na₂CO₃)等物质作原料来制备少量氢氧化钠

阅读理解。

     It's seven thirty now. It's time to go to school. Our classroom is behind the trees. It's very nice. There is

a map of China on the wall. Twenty boys and fifteen girls are in the classroom. There are some flowers on the

teacher's desk. They are for our teachers. We have four classes in the morning and two in the afternoon. We

aren't at school on Sunday.

1. The students go to school at _______.

A. 7: 13

B. 7: 03

C. 7: 30

2. Their classroom is ________ some trees.

A. behind

B. in

C. under

3. A map of China is on the ________.

A. desk

B. wall

C. blackboard

4. The ________ are for the teachers.

A. maps

B. desks

C. flowers

5. There are ________ students in this class.

A. forty-five

B. fifteen

C. thirty-five