铅蓄电池电解液的液面会降低，主要原因后是（）。A．充电时，电解液会飞溅出来 B．放电

选出下列词语书写全对的一项    [ ]

A．寸积铢累　浮光掠影　物竟天择   

B．家喻户晓　错踪复杂　一触即破  

C．鞭辟人里　融会贯同　举一反三   

D．肃然起敬　灯火阑珊　劳而无功

两个相距很近的等量异种点电荷组成的系统称为电偶极子．设相距为l，电荷量分别为+q和-q的点电荷构成电偶极子，如图所示．取二者连线方向为y轴方向，中点O为原点，建立如图所示的xOy坐标系，p点距坐标原点O的距离为r（r＞＞l），p、O两点间的连线与y轴正方向的夹角为θ，设无穷远处的电势为零，p点的电势为φ，真空中静电力常量为k．下面给出φ的四个表达式，其中只有一个是合理的．你可能不会求解p点的电势φ，但是你可以通过一定的物理分析，对下列表达式的合理性做出判断．根据你的判断，φ的合理表达式应为（　　）

A．φ=

B．φ=

C．φ=

D．φ=

一组数据1，4，2，5，3的中位数是______．

下列各项中哪项不是散剂的特点（）

A.不易变质

B.服用方便

C.吸收缓慢

D.节省药材

E.制备简便

Naturalist: For decades we have known that the tuatara, a New Zealand reptile, have been approaching extinction on the South Island. But since South Island tuatara were thought to be of the same species as North Island tuatara there was no need to protect them. But new research indicates that the South Island tuatara are a distinct species, found only in that location. Because it is now known that if the South Island tuatara are lost an entire species will thereby be lost, human beings are now obliged to prevent their extinction, even if it means killing many of their unendangered natural predators.
Which one of the following principles most helps to justify the naturalists’ argumentation

A．In order to maximize the number of living things on Earth, steps should be taken to preserve all local populations of animals.

B．When an animal is in danger of dying, there is an obligation to help save its life, if doing so would not interfere with the health or well-being of other animals or people.

C．The threat of local extinction imposes no obligation to try to prevent that extinction, whereas the threat of global extinction does impose such an obligation.

D．Human activities that either intentionally or unintentionally threaten the survival of an animal species ought to be curtailed.

E．(E) Species that are found in only one circumscribed geographical region ought to be given more care and attention than are other species because they are more vulnerable to extinction.