在图中数据流程图的基本符号中，符号D2维护表示（）。 A.“维护”数据存储 B.“维

按照买方类型的不同，可将市场分为（）

A.商品市场

B.服务市场

C.组织市场

D.金融市场

E.消费者市场

寒假小明要从兰州到广州去探望爷爷：

①选择最经济的交通工具是_________ ；②沿途经过的铁路干线是__________ 、__________ ；

③请写出兰州所在省的简称_______ ，广州所在省的简称_______ 。

阅读理解。

     More than 6,000 children were expelled (开除) from US schools last year for bringing guns and bombs

to school, the US Department of Education said on May 8.

     The department gave a report on the expulsions (开除) as saying hand-guns accounted for 58 percent

of the 6,093 expulsions in 1996-1997, against 7 percent for rifles (步枪) or shot-guns and 35 percent for

other types of firearms.

     "The report is a clear sign that our nation's public schools are cracking down (严惩) on students who

bring guns to school," Education Secretary Richard Riley said in a statement. "We need to be tough-minded

about keeping guns out of our schools and do everything to keep our children safe."

     In March 1997, an 11-year-old boy and a 13-year-old boy using handguns and rifles shot dead four

children and a teacher at a school in Jonesboro, Arkansas. In October, two were killed and seven wounded

in a shooting at a Mississippi school. Two months later, a 14-year-old boy killed three high school students

and wounded five in Daducah, Kentucky.

     Most of the expulsions, 56 percent, were from high schools, which have students from about age 13. 34

percent were from junior high schools and 9 percent were from elementary schools, the report said.

1. From the first paragraph we can infer that in the US schools ____.

A. students enjoy shooting

B. students are eager to be soldiers

C. safety is a problem

D. students can make guns

2. The report from the US Department of Education shows that ____.

A. the number of the expulsions is not large

B. the number of the expulsions is wrong

C. there are soldiers hiding among the students

D. guns are out of' control in US schools

3. The main idea of paragraph four shows us ____.

A. some examples of shootings in US schools

B. the Americans' feeling

C. some famous schools

D. that some teachers were killed by students

4. From this passage we know that ____.

A. every American cannot have guns

B. only soldiers and police can have guns

C. every American citizen can own guns

D. teachers have on money to buy guns

某外来化合物在狗、免、大鼠、小鼠、猴的LD50值分别为20mg/kg、10mg/kg、100mg/kg、50mg/kg、40mg/kg。据此资料，该化合物LD50的物种差异系数为

A．10
B．20
C．40
D．60
E．80

根据《房屋建筑和市政基础设施工程施工分包管理办法》的规定，对于接受转包、违法分包和利用他人名义承揽工程的单位，处以（）的罚款。

A.1万元以上3万元以下

B.合同金额2%以上4%以下

C.合同金额0.5%以上1%以下

D.50万元以上100万元以下