患者，女，38岁。患白细胞减少症。面色无华，疲倦无力，头晕目眩，少寐多梦，纳呆食少，

清灰时不能破坏粉尘初层，以免降低除尘效率，以下影响袋式除尘器除尘效率的因素有（）。

A.过滤风速

B.压力损失

C.滤料的性质

D.清灰方式

You can speak to people on other side of the earth over the telephone with help of a satellite. They can help to take photos on the earth and produce maps. Some pictures taking by satellites show us the exact place where different metals can be found. They can also tell the differences between healthy plants or poor ones. This is a great help to the scientists work in forestry and in agriculture. Satellites benefit by out daily life. For example, satellites for broadcasting are used to sending radio and TV programmes from one part of the world to other. It is the satellites to make our world seem smaller.

（）开办网上银行业务，应由其总行统一向中国银监会的当地派出机构申请。

A.政策性银行

B.城市商业银行

C.外资银行

D.外国银行分行

机械传动式轨道车主要传动部件为（）。

A.皮带

B.齿轮

C.链条

D.传动轴

简述阀门密封填料的质量标准？