生于指腹部的疔疮称为（）。 A.螺疔 B.蛇头疔 C.蛇眼疔 D.蛀节疔 E.鱼肚抒

大量调查表明，某市区女孩平均出生体重3.0Kg，现有16名男孩，测得其平均出生体重为3.50k，标准差为0.50起。

推测3.0与3.50两个数值存在差异的可能原因是（）。

A.个体差异

B.抽样误差

C.总体均数不同

D.个体差异或总体均数不同

E.抽样误差或总体均数不同

成年人以神经胶质瘤和脑膜瘤多见，发生率最高的部位是()

A．鞍区、脑桥小脑角

B．脑室内

C．脑干

D．小脑

E．大脑半球

阅读理解。

     Having a husband means an extra seven hours of housework each week for women, according to a new

study. For men, getting married saves an hour of housework a week. "It's a well-known pattern," said lead

researcher Frank Stafford at University of Michigan's Institute for Social Research. "Men usually work more

outside the home, while women take on more of the housework."

     He points out that differences among households (家庭) exist. But in general, marriage means more

housework for women and less for men. "And the situation gets worse for women when they have children."

Stafford said.

     Overall, times are changing in the American home. In 1976, women busied themselves with 26 weekly

hours of sweeping-and-dusting work, compared with 17 hours in 2005. Men are taking on more housework,

more than doubling their housework hours from six in 1976 to 13 in 2005.

     Single women in their 20s and 30s did the least housework, about 12 weekly hours, while married women

in their 60s and 70s did the most-about 21 hours a week.

     Men showed a somewhat different pattern, with older men picking up the broom more often than younger

men. Single men worked the hardest around the house, more than that of all other age groups of married men.

     Having children increases housework even further. With more than three, for example, wives took on more

of the extra work, clocking about 28 hours a week compared with husbands' 10 hours.

1. According to the"well-known pattern" in Paragraph 1, a married man _____.

A. takes on heavier work

B. does more housework

C. is the main breadwinner

D. is the master of the house

2. How many hours of housework did men do every week in the 1970s?

A. About 28

B. About 26

C. About 13

D. About 6

3. What kind of man is doing most housework according to the text?

A. An unmarried man.

B. An older married man.

C. A younger married man.

D. A married man with children.

4. What can we conclude from Stafford's research?

A. Marriage gives men more freedom.

B. Marriage has effects on job choices.

C. Housework sharing changes over time.

D. Having children means doubled housework.

下列物质中，只含有非极性共价键的是[ ]

A.NaOH

B.NaCl

C.H₂

D.H₂S

焦炉煤气的爆炸限度是（）。

A.6—30%

B.40—70%

C.42—74%