关于黄河的叙述，正确的是（ ） A．黄河的中游是“地上河” B．黄河为世界上含沙

五年级一班有48名同学排队做操，要求每行的人数相同，有几种不同的排法？

在电气设备上工作，保证安全的组织措施为：工作票（操作票）制度；（）制度；（）制度；（）转移和总结制度。

Conservationists have believed that by concentrating their preservation efforts on habitats rich in an easily surveyed group of species, such as birds, they would thereby be preserving areas rich in overall species diversity. This belief rests on a view that a geographical area rich in one group of species will also be rich in the other group’s characteristic of the entire regional climate zone.
Which of the following findings about widely scattered tracts 10 kilometers by 10 kilometers in a temperate climate zone would most seriously challenge the conservationists’ assumptions

A．The tracts show little damage from human intrusion and from pollution by human activities.

B．Where a certain group of species, such as birds, is abundant, there is also an abundance of the species, such as insects, on which that group of species feeds, or in the case of plants, of the land and water resources it requires.

C．The area of one of the tracts is generally large enough to contain a representative sample of the organisms in the region.

D．There is little overlap between the list of tracts that are rich in species of butterflies and the list of those that are rich in species of birds.

E．(E) The highest concentration of individuals of rare species is found where the general diversity of species is greatest.

招聘的预算一般包括( )。

A．获取中介信息而支付的费用

B．在电视、报纸等媒体发布广告等费用

C．组织招聘人员的工资、福利、差旅费等费用

D．租用临时设备、办公用具等费用

E．招聘人员的个人开支

X18次是（）。

A.货运五定班列

B.旅游列车

C.临时旅客列车

D.特快行邮列车