MPLS技术的核心是______交换。

铝合金在军用装备上广泛地取代了钢，因为它能提供同样的防护而重量更轻。但是一辆铝合金装甲车的制造成本是钢装甲车的两倍。因此，从财政的角度看，用具有同样防护性能的铝合金装甲车来代替钢装甲车的做法是不可取的 以上哪项为真，则能够对上述结论提出最大的质疑

A．铝合金装甲车投入使用后的运行成本是同样性能的钢装甲车的三分之一

B．引进铝合金装甲车后，军队必须保留维修人员并购买新的工具和零件

C．钢装甲车的维修成本在军队目前所使用的各种装甲车中是最低的

D．预计铝合金材料的价格将保持稳定，而钢材的价格有可能下降

为了促进儿童骨骼的正常生长发育，应给儿童补充[ ]

A．含钙丰富的食物          

B．含磷丰富的食物  

C．含钙和磷丰富的食物      

D．含钙、磷和维生素D多的食物

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.

小题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小题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小题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.小题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.

兼可抑制原、真核生物蛋白质生物合成的抗生素是（）

A.链霉素

B.氯霉素

C.红霉素

D.放线菌酮

E.嘌呤霉素

根据《固定电话交换设备安装工程验收规范》（YD/T5077—2005），在程控交换设备安装工程验收以前，必须对机房在环境（）方面进行全面检查。

A.机房及走廊等地段土建工程全部竣工

B.机房插座及照明数量配备符合要求，满足使用条件

C.机房空调设备性能良好，室内温湿度满足规定要求

D.对老机房活动地板应专门检查，铺设符合设计要求

E.把机房窗户全部打开通风