碎片现象的存在使得( )。 A．内存空间利用率降低 B．内存空间利用率提高 C．内

阅读理解。

     My name is ZhanTao. I'm a student. I'm thirteen. My father is a teacher. He teaches math. My mother is

a teacher too. She is an English teacher. We are Chinese. But now we are in England. This is a photo of my

friends. His name is Tom. He is an English boy. He is my best friend.  The girl is Anise. She is an American girl.We are all good friends.

1. What's the boy's name?

A. Anny.

B. Jenny.

C. Zhan Tao.

2. How old is the boy?

A. Twenty.

B. I don't know.

C. He is thirteen.

3. What's his father's job?

A. A worker.

B. A doctor.

C. A teacher.

4. Is his mother an English teacher?

A. Yes, she is.

B. No, she doesn't.

C. Yes, she does.

5. Is the boy Chinese or English?

A. Chinese.

B. English.

C. I don't know.

为了维护人类社会的正义、公平，追求文明社会的和谐发展，人类创造了法律。被恩格斯称为“第一个世界性法律”的法典是                 （   ）

A．中国的《秦律》

B．《查士丁尼民法大全》

C．《法国民法典》

D．英国的《大 * * 》

在简单线性回归分析中，得到回归系数为-0.30，经检验有统计学意义，说明______.

A．X对Y的影响占Y变异的30%

B．X增加一个单位，Y平均减少30%

C．X增加一个单位，Y平均减少0.30个单位

D．Y增加一个单位，X平均减少30%

E．Y增加一个单位，X平均减少0.30个单位

如图一辆质量为1000kg的汽车静止在一座半径为40m的圆弧形拱桥顶部．（取g=10m/s²）

（1）此时汽车对圆弧形拱桥的支持力是多大？

（2）如果汽车以6m/s的速度经过拱桥的顶部，则汽车对圆弧形拱桥的压力是多大？

（3）汽车以多大速度通过拱桥的顶部时，汽车对圆弧形拱桥的压力恰好为零？

现浇水泥蛭石保温隔热层，夏季施工时应选用下列哪种水泥？（）

A.火山灰水泥

B.粉煤灰水泥

C.硅酸盐水泥

D.矿渣水泥