澄江动物群

质量为m=3kg的木块，放在水平地面上，木块与地面的动摩擦因数μ=0.5，现对木块施加F=30N，方向与水平方向成θ=370的拉力，如图所示，木块运动4s后撤去拉力F直到木块停止．（sin37°=0.6，cos37°=0.8，g=10m/s²）求

（1）撤去拉力F时木块的速度为多大；

（2）木块在水平面上运动的位移为多少．

25℃时，将0.01 molCH₃COONa和0.002 mol HCl溶于水，形成1L混合溶液：

(1)该溶液中存在着三个平衡体系，用电离方程式或离子方程式表示： ①____； ②_____； ③____。

(2)溶液中共有___种不同的粒子（指分子和离子）。

(3)在这些粒子中，浓度为0.01 mol·L^-1的是____，浓度为0. 002 mol·L^-1的是____。

(4)____和___两种粒子物质的量之和等于0.01 mol。

阅读理解。

     Attractive fathers do not pass their looks onto their sons but they will hand their good looks down to their

daughters, research shows.

     In a study of family photographs, Professor David Perrett and Elisabeth Cornwell-now at the University of

Colorado have found that while both father and mother can influence the attractiveness of their daughters, the

couple's good looks do not necessarily contribute to the attractiveness of their son as an adult. Handsome men

with masculine (阳刚的) looks are likely to pass on masculine features, but not facial attractiveness.

     The theory suggests it is not unusual for attractive parents to produce a beautiful daughter while failing to

pass on the same good looks to a son.

     While many celebrity mothers produce beautiful daughters-such as Goldie Hawn and her daughter Kate

Hudson or Jerry Hall and her daughter Georgia-the same is not necessarily true of celebrity fathers. Sean

Stewart, the son of Rod Stewart and his first wife Alan, would probably be judged less attractive than his model

sister Kimberly. "We can't see a strong relationship between the parents' attractiveness and the sons. If the

parents are supermodels, their daughters will be lookers," Perrett said.

     Prof Perrett said it has previously been suggested that a woman could increase her own reproductivets (繁

殖的) success by choosing a good-looking man whose genes would be passed onto male children. But the new

study, published in the current edition of the journal Animal Behaviour, disagrees with the theory.

     He said:"When we looked at women's faces, we found clear evidence that attractiveness passed from both

father and mother to daughter. For the male line, we find that facial masculinity follows the rule 'like father like

son'. Masculine dads have masculine sons. But we did not find any evidence that facial attractiveness is passed

from father to son."

1. Which of the followings is TRUE according to the passage? [ ]

A. Father and mother can influence the attractiveness of their children.

B. Handsome fathers with masculine looks will not pass on masculine features.

C. There is a strong relationship between the parents' attractiveness and the daughters.

D. If the parents are supermodels, their sons will be good-looking.

2. What does the word "lookers" in the fourth paragraph most probably mean? [ ]

A. On-lookers.

B. Models.

C. Beauties.

D. Passers-by.

3. How many celebrity families are mentioned in the passage? [ ]

A. Three.

B. One.

C. Two.

D. Four.

4. The passage is most likely to be found in a book about _____. [ ]

A. popular science

B. historical events

C. successful people

D. political systems

用一定的开采工艺，按一定的开采顺序，剥离岩石、采出矿石的方法是( )。

A．露天开采

B．空场采矿法

C．柱式体系采煤法

D．阶段采矿法

受电弓对接触线的静压力为（）。